Imran's Knowledge Base World

Failed to Load Resource - Safari issue

2011-06-28T06:40:00.001-07:00

Hello All,

Recently application stopped working on Safari with issue 'Failed to Load Resource'. The scenario is; the web page send AJAX-Request to an aspx page and show the output into html container. The issue occurred when the request comes form https and with Safari. Basically all WebKit based browser having same issue, like Chrome and Safari.

Post has been moved to beyondrelational.com

An error occurred while opening the queue:Access is denied - MSMQ exception

2011-06-26T03:18:00.001-07:00

System.ServiceModel.MsmqException: An error occurred while opening the queue:Access is denied. (-1072824283, 0xc00e0025). The message cannot be sent or received from the queue. Ensure that MSMQ is installed and running. Also ensure that the queue is available to open with the required access mode and authorization.

This post has been moved to beyondrelational.

Failed to complete setup of assembly (hr = 0x8007000b). Probing terminated – Windows7 64bit - Solved

2011-06-02T01:36:00.001-07:00

It have been long I wrote blog, planning to start this join once again

Recently I changed my desktop from 32bit to 64bit Windows 7 and from there onwards I keep getting such issues. In such case when you run web page which gives following error.

Error : Could not load file or assembly 'XXX.XXXXXX' or one of its dependencies. An attempt was made to load a program with an incorrect format.

Error: Failed to complete setup of assembly (hr = 0x8007000b). Probing terminated.

Domain name replaced with Machine Name in WCF Service

2010-07-31T11:11:00.000-07:00

This post has been moved to beyondrelational.

How to get multiple result set of procedure using LINQ to SQL

2010-07-17T10:12:00.001-07:00

There always be case where one procedure returns more then one result set. Getting those data in DataSet is lazy way of coding, best way to do that is using DataReader. DataReader having method call NextResult which allows us to read next result set if any.

How to add method in Sealed class

2010-07-16T10:03:00.001-07:00

It is possible with C# 3.0 to add method into sealed class. For more details please visit following link

http://beyondrelational.com/blogs/ibhadelia/archive/2010/07/16/how-to-add-method-in-sealed-class.aspx

OperationFormatter could not serialize error with WCF

2010-06-24T11:14:00.000-07:00

I was working with calling WCF from iPhone, I have posted one post on “how can you call WCF from iPhone” you can find here. While I was working with this, I faced this issue and after doing some research I found solution! Here is what I did.

Following operation contract works fine.

[OperationContract]
public Dictionary<string, string> GetDictionary()

Note that I have only put operation contract not decoration which needed to work WCF with iPhone and Json.
But if we change this that operation contract to following...

[OperationContract]
public string GetDictionary()

After doing this I started getting follwoing error.

The OperationFormatter could not serialize any information from the Message because the Message is empty

I was wondering as it was issue with primitive type string! where it was working find with complex type. I searched a lot but did not get any solution for this. The service was retuning Serialized Json data; but not sure what was wrong there. I was searching for workaround to this but didn’t find any then I wrap that string into concert class and and return that class object, and you don’t believe it works fine! Error is gone I fixed The OperationFormatter could not serialize any information from the Message because the Message is empty error, wow!!!!!

I have modified operation and now it looks like following.

[DataContract]
public class Response
{
    [DataMember]
    public string Data { get; set; }
}

[OperationContract]
public Response GetDictionary()
{
    return new Response() { Data = "success" };
}

It still open question why it was not working in only string, however it was working with Dictionary object and then with Abstract type! I assume that at the time of serializing request its not able to create object of string as its primitive type! Not sure its true but it works fine with wrapper.

wsdl-service-soap-address location having machine name not domain name

2010-06-22T19:30:00.000-07:00

After fixing “Domain name replaced with machine name in WCF Service”, you can find solution in my previous post.

I found same issue but somewhere else, when you look into wsdl at the end where all services are listed there still machine name exists.

And hence any of the client will have following error.

There was no endpoint listening at http://domainname/ServiceName.svc that could accept the message. This is often caused by an incorrect address or SOAP action.

That is because it still uses computer name in soap address not domain name. Lets fix this issue too. We have to simply change endpoint address nothing more.

<services>
  <service behaviorConfiguration="serviceBehaviour" name="Demo.Service.MultiEndPointsService">
    <endpoint address="http://192.168.1.2/Demo.Service/MultiEndPointsService.svc/basic" binding="basicHttpBinding" bindingConfiguration="basicBinding"
      contract="Demo.Service.MultiEndPointsService" />
  </service>
</services>
<behaviors>
  <serviceBehaviors>
    <behavior name="serviceBehaviour">
      <serviceMetadata httpGetEnabled="true" httpGetUrl="http://192.168.1.2/Demo.Service/MultiEndPointsService.svc/basic"/>
      <serviceDebug includeExceptionDetailInFaults="false" />
    </behavior>
  </serviceBehaviors>
</behaviors>

Now let’s how wsdl looks like.

We are good to go!

Domain name replaced with Machine Name in WCF Service

2010-06-22T05:30:00.000-07:00

I personally came across this issue WCF was taking machine name not IP address or domain name and also I got questions from forums about “how to replaced Machine Name with Domain name in WCF Service wsdl link?”. This occurs when we host WCF service on IIS then the links to wsdl is uses local machine name not the domain name or IP address.

You can see in browser [here I used IP address of my machine] in wsdl link its adding my computer name, this is same issue when I publish this service on production; the wsdl link is taking name of production machine not domain.

I found some solutions which changes the bindings on server but again that is not helpful for me on production server however it works well on local machine.

Then I was checking the configurations and found solution for how Domain name replaced with Machine Name in WCF Service without playing with IIS bindings. In service behavior we can change the behavior of serviceMetadata which will FIX our problem. We need to specify on what location metadata will resides httpGetUrl or httpsGetUrl. We can add url having domain rather machine name. So final configuration should look like following which is our solution.

<system.serviceModel>
  <services>
    <service name="Demo.Service.MultiEndPointsService" behaviorConfiguration="serviceBehaviour">          
      <endpoint address="basic" binding="basicHttpBinding" bindingConfiguration="basicBinding" contract="Demo.Service.MultiEndPointsService" />
    </service>
  </services>
  <behaviors>
    <serviceBehaviors>
      <behavior name="serviceBehaviour">
        <serviceMetadata httpGetEnabled="true" httpGetUrl="http://192.168.3.61/Demo.Service/MultiEndPointsService.svc/basic"  />
        <serviceDebug includeExceptionDetailInFaults="false" />
      </behavior>
    </serviceBehaviors>
  </behaviors>
  <bindings>
    <basicHttpBinding>
      <binding name="basicBinding" maxBufferSize="2147483647" maxReceivedMessageSize="2147483647">
        <security mode="None"></security>
        <readerQuotas maxStringContentLength="2147483647" />
      </binding>
    </basicHttpBinding>
  </bindings>
</system.serviceModel>

You can see value of httpGetUrl; I have specified IP address

Now let’s see again in browser.

There you goo!!!

Calling WCF service from iPhone

2010-06-21T09:52:00.000-07:00

WCF changes way of communication between application-to-application and intra-application. This post will help you to call WCF from iPhone application. First we will see what we have to do on WCF to let iPhone application call service. And the sample code which call WCF from iPhone.

First let’s create simple WCF service.

[ServiceContract(Namespace = "")]
[DataContractFormat]
public class MultiEndPointsService
{
    [OperationContract]
    public string GetDictionary()
    {
        Dictionary<string, string> dict = new Dictionary<string, string>();
        dict.Add("IB", "Imran Bhadelia");
        dict.Add("DO", "David Oliver");
        dict.Add("NA", "Nick Althoff");
        dict.Add("JJ", "Jay Joshi");
        dict.Add("DL", "Dave Larson");
        dict.Add("BA", "Brenda Ayong-Chee");
        dict.Add("JP", "Jay Parikh");

        StringBuilder sbJson = new StringBuilder();
        new JavaScriptSerializer().Serialize(dict, sbJson);
        return sbJson.ToString();

    }
}

This is simple WCF Service. We need to add some decoration for enabling web script and handle POST method. We are going to send http post form iPhone application and send Json string as response. Doing so we also need to decorate our operation contract to set request and response format.

[ServiceContract(Namespace = "")]
[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
[ServiceBehaviorAttribute(IncludeExceptionDetailInFaults = true)]
[DataContractFormat(Style = OperationFormatStyle.Document)]
public class MultiEndPointsService
{
    [WebInvoke(Method = "POST", BodyStyle = WebMessageBodyStyle.WrappedRequest,
        RequestFormat = WebMessageFormat.Xml, ResponseFormat = WebMessageFormat.Json)]
    [OperationContract]
    public string GetDictionary()
    {
        Dictionary<string, string> dict = new Dictionary<string, string>();
        dict.Add("IB", "Imran Bhadelia");
        dict.Add("DO", "David Oliver");
        dict.Add("NA", "Nick Althoff");
        dict.Add("JJ", "Jay Joshi");
        dict.Add("DL", "Dave Larson");
        dict.Add("BA", "Brenda Ayong-Chee");
        dict.Add("JP", "Jay Parikh");
           
        StringBuilder sbJson = new StringBuilder();
        new JavaScriptSerializer().Serialize(dict, sbJson);
        return sbJson.ToString();
    }
}

And following are the configuration settings

<system.serviceModel>
    <services>
      <service name="Demo.Service.MultiEndPointsService" behaviorConfiguration="serviceBehaviour">
        <endpoint address="basic" binding="basicHttpBinding" bindingConfiguration="basicBinding" contract="Demo.Service.MultiEndPointsService" />
      </service>
    </services>
    <behaviors>
      <serviceBehaviors>
        <behavior name="serviceBehaviour">
          <serviceMetadata httpGetEnabled="true" />
          <serviceDebug includeExceptionDetailInFaults="false" />
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <bindings>
      <basicHttpBinding>
        <binding name="basicBinding" maxBufferSize="2147483647" maxReceivedMessageSize="2147483647">
          <security mode="None"></security>
          <readerQuotas maxStringContentLength="2147483647" />
        </binding>
      </basicHttpBinding>    
    </bindings>
  </system.serviceModel>

We need to create basicHttpBinding so it get called form iPhone application, we haven’t sent security to call this method; and following is the Objective-C code which call WCF from iPhone.

NSString *soapMessage = [NSString stringWithFormat:@"<SOAP-ENV:Envelope xmlns:SOAP-ENV=\"http://schemas.xmlsoap.org/soap/envelope/\"><SOAP-ENV:Body><GetDictionary></GetDictionary></SOAP-ENV:Body></SOAP-ENV:Envelope>"];
   
NSURL *url = [NSURL URLWithString:@http://localhost/Demo.Service/MultiEndPointsService.svc/basic];
NSMutableURLRequest *theRequest = [NSMutableURLRequest requestWithURL:url];                        
NSString *msgLength = [NSString stringWithFormat:@"%d", [soapMessage length]];             
   
[theRequest addValue: @"text/xml; charset=utf-8" forHTTPHeaderField:@"Content-Type"];
[theRequest addValue: @"urn:MultiEndPointsService/GetDictionary" forHTTPHeaderField:@"SOAPAction"];
[theRequest addValue: msgLength forHTTPHeaderField:@"Content-Length"];
[theRequest setHTTPMethod:@"POST"];    
[theRequest setHTTPBody: [soapMessage dataUsingEncoding:NSUTF8StringEncoding]];

NSURLConnection *theConnection = [[NSURLConnection alloc] initWithRequest:theRequest delegate:self];

Once you parse the response it will look like following.

You can also call operation contract having parameters, for that need to create proper message and then add it in SOAP-BODY that will work.

WCF Service with webHttpBinding-basicHttpBinding-wsHttpBinding

2010-06-20T04:51:00.001-07:00

WCF Services are designed to support distributed services where consumed client. Services are typically have WSDL interface which any of client can consumed regardless of platform on which WCF is hosted on.

WCF Services having three portions, Class having methods, host environment to host service, and one or more endpoints. Endpoints is place where WCF Client connects to WCF Service. In order to accommodate different communication scenario you just need to create more then one endpoints, for each endpoint you specify the address, a binding and a contract. Address is simple listener; contract specify the format of message which will arrive on specified address and binding is let you configure transport protocol, encoding and security. There are few built-in bindings represented by System.ServiceModel.Channels.Binding class to support HTTP, TCP and MSMQ protocols.

That was brief about WCF, now lets come to our business. We need to use wsHttpBinding + basicHttpBinding + webHttpBinding all together. That means we need to have multiple ends points to our service for different-different scenario. Here are the Service contract and operation contracts which we are going to use.

We will add one by one binding and check into WCF Test Client. First we will add basicHttpBinding which is designed for interoperability utmost important, its using SOAP 1.1.

You can see single endpoints having address and bindings, we have added binding configuration name basicBinding, which have property like security mode to None, readerQuotas having setting for client who is reading data from channel, also maxBufferSize which is parameter defined size which can be passed thru channel. We can see bindings in WCF Test Client it will show basic http bindings having one method. The value of maxBufferSize and maxReceivedMessgaeSize should be same for transfer mode is buffered. We have added behavior configuration for our service; serviceMetadata httpGetEnabled="true" allows simple HTTP Get request to succeed for metadata retrieval, by default WCF does not exposed metadata.

We can use WCF Test Client to check whether our setting are correct or not. So open WCF Test Client and add service url into service project.

It shows that we have exposed our service using basicHttpBinding. Now lets add wsHttpBinding binding, which is design for security, reliable messaging and transactions and its using SOAP 1.2 along with WS-Addressing 1.0 for message version which will carry additional protocol headers.

We have added binding configuration to set security and session reliability. The reliable session WCF provides ensures that messages sent between endpoints are transferred across SOAP or transport intermediaries and are delivered only once and, optionally, in the same order in which they were sent

Now let’s check on our WCF Test Client.

So, we can see two endpoints has been exposed, one is for basic binding and other is web script bindings. We already add basic and ws bindings lets add now web bindings.

One more endpoint, it’s now easy to expose more then one endpoint for single operation contract. If you need any security or additional settings then you can add binding configuration for this endpoint, but for now we don’t need any configurations. Let’s check our WCF Test Client.

We can see all these three binding for single operation contract! You can see wsdl file which will expose all these three bindings.

So we have exposed webHttpBinding + basicHttpBinding + wsHttpBinding endpoints in WCF service using same operation contract. We can use webHttpBinding for Silverlight application and also Json call.

RadComboBox dropdown issue in IE

2010-06-14T11:08:00.000-07:00

Hello All, I was facing issue with RadComboBox dropdown, its adding scrollbar in IE if an item is longer then default size.

This is normal behavior, as we have item which get fits into dropdown, now consider following case where we items which are little longer then before.

Here you can see horizontal scrollbar is appear as our text is little bit longer then min-width property. Min-width property allow you to set minimum width of dropdown. But this looks weird.

Solution: You need to override following default style of RadComboBox.

<style>
    .rcbSlide div
    {
        width: auto !important;
        min-width: 150px !important;
        max-width: 400px !important;
    }
    .rcbList
    {
        position: relative !important;
    }
</style>

We can see after applying this style into page, RadComboBox will look like following.

HTTP Error 404.17 - Not Found with IIS7 and WCF

2010-04-17T00:10:00.000-07:00

Hello All,

I was running to same issue when I have installed VS2010 on Windows 7 after installing .NET on IIS 7.5. My WCF service was retuning me the following error when I try to hit my wcf service it will giving me following error.

HTTP Error 404.17 - Not Found

I tried to change application pool and switch form 2.0 classic to 4.0 class, and then it gives me one more error!

HTTP Error 500.19 – Internal Server Error
The requested page cannot be accessed because the related configuration data for the page is invalid.

Error Code 0×800700b7
Config Error There is a duplicate ’system.web.extensions/scripting/scriptResourceHandler’ section defined

After doing some search I found out the fix of this, we just need to register service model using following command, you should run command prompt in administrator mode and then go to following directory.

$WindowsDir$\Microsoft.NET\Framework\v3.0\Windows Communication Foundation

And run this command in favor to register service model.

servicemodelreg –i

It will install machine configuration sections, handlers, assemblies, modules, protocols and lots of other thing to work things properly.

Two WCF Sharing same a Data Contract - Ambiguous Error

2010-03-16T03:54:00.000-07:00

[Problem: Ambiguous reference]

Hello All,

I came across one common issue while working with WCF services, Two WCF exposing same data contract with different namespace. Here are my two service contract with operation contracts.

namespace SVCDataContractTest.WCF
{
    [ServiceContract]
    public interface IService1
    {
        [OperationContract]
        void DoWork(UserInfo userInfo);

        [OperationContract]
        void SaveContact(ContactInfo contactInfo);

    }

    public class Service1 : IService1
    {
        public void DoWork(UserInfo userInfo)
        {
            //Do some work
        }

        public void SaveContact(ContactInfo contactInfo)
        {
            //Do some work
        }
    }

    [ServiceContract]
    public interface IService2
    {
        [OperationContract]
        UserInfo DoWork();
    }

    public class Service2 : IService2
    {
        public UserInfo DoWork()
        {
            //Do some work
            return new UserInfo();
        }
    }
}

While adding them as reference it will generate two separate class having different namespace, we are good here as there won't be any compilation error if a requester don't import both namespace.

You can see there two UserInfo classes. Now problem comes when you imported both of the namespace, what happen to your class? it will start giving you following error.

It says that UserInfo is an ambiguous, as there are two set of classes resides in reference. The problem is when you add Service reference it's not treating UserInfo class as Shared class. Solution for this is to create Proxy with Type Sharing. We can use wsdl.exe to create proxy with shareType switch

wsdl.exe /out:ServiceProxies.cs /shareTypes http://localhost/SVCDataContractTest.WCF/Service1.svc?wsdl http://localhost/SVCDataContractTest.WCF/Service2.svc?wsdl

This will result in one class file called ServiceProxies, which contains the proxy implementation of both service but the implementation of UserInfo will be single.

Schema and Data Compare Scripts in MS SQL

2009-12-10T06:02:00.000-08:00

Hello All,

I was searching for a tool which gives me the Schema and or data comparison for SQL Server, its really needed while we are updating staging or updating our live site. There may be lots of tool available on net but I found one tool which is part of Microsoft® Visual Studio Team System 2008 Database Edition GDR R2.

Team Edition provides lots of functionality, mainly we are using to write Test Case which is very useful for Test Driven Development.

On top of this if you have Database edition then you can do lots of things with it. One of the feature is Schema and Data Compare. This blog post will walk you thru steps to compare data and schema.

Schema Comparison

1. Go to New Schema Comparison form Data menu

2. Next select the two database, one is source and other is target

3. When press OK will give you the Schema Compare of all the objects including Tables, Views, Stored Procedures and many more.

Here you can see the list of Objects and the Object Definitions windows

4. In following image Table is expanded so you can see the changes in details on what table what action is held.

5. To see more in details select one of the updated row and you can see the definition in Object Definitions window; it will generate Create script and highlight the difference. There is also Schema Update Script which will have alter script of all the changes that is detected during Schema Compare.

6. You can either copy the script or export to file or editor by using Export To Edition command on tool box.

This was all about how to detect schema change, its very handy with lots of options.

Data Comparison

Now same way we have Data Comparison, which is use to compare data, it provides tons of details and script for insert/update and delete. The steps are pretty much starlight forward. I have listed the steps here.

1. Click on New Data Comparison from Data menu

2. It will ask for Source and Target tables

3. On click of Finish, it will provide you all the information that is differ in between two database tables

You can see here it shows 2 rows are only in source, means two rows are added to SB_mst_Group table. It also provides the what exact rows are added in middle section along with other options.

In third last section which is Data Update Script; provides you the script for the action, here we have addition, so its provide the insert statements which we can run in UAT to get the date.

I found it very useful and easy to generate required script in few mouse click!

Consuming WCF service out of box

2009-11-25T04:58:00.000-08:00

Hello All,

I found one issue while consuming WCF service from out of box, There are lots of threads I found for 'The communication object, System.ServiceModel.Channels.ServiceChannel, cannot be used for communication because it is in the Faulted state.' error, CommunicationObjectFaultedException exception thrown and 'The caller was not authenticated by the service.'

I spent lots of time in search, got bunch of solutions, some worked some does not, after doing lots of troubleshooting I got solution for my problem.

My case was, a web application running on different box is trying to consume WCF service which is hosted on different box, but some how on production it was not working. It always throws 'CommunicationObjectFaultedException'. Usually we are putting such calls in using blog, as its taking care of disposing object. But in case of WCF it may not work as per expected, the reason is; A CommunicationObjectFaultedException has been throws so you, the object is not yet initialized and you are using is trying to dispose method which again throw exception.

This is because using implicitly call Dispose at the closing brace, which may throw an exception because your object is not yet initialized as its in the Faulted state. To over come this a simple solution, use try catch and call Abort. More reading on this click Avoiding Problems with the Using Statement, good article form Microsoft including Sample application. During my search I found one good code delegate make you fell like you are using clause, but internally its handling such exception.

private class Util
{
    public static void UsingWcf<T>(T client, Action<T> action)
        where T : System.ServiceModel.ICommunicationObject
    {

        try
        {
            action(client);
            client.Close();
        }
        catch (Exception)
        {
            client.Abort();
            throw;
        }
    }
}
class Program
{
    static void Main(string[] args)
    {

        Util.UsingWcf(new WcfClient(), c =>
            {

            });

        /*using (WcfClient wcfClient = new WcfClient())
        {
            ....
        }// This will throw an error 
         */
    }
}

So we have caught CommunicationObjectFaultedException, but still we are not able to make call to service method. Now you can see one new error 'The caller was not authenticated by the service'. Cool we reach the service but its missing some credentials, as we are consuming service out of box.

Typical configuration section looks like following

Form error 'The caller was not authenticated by the service' we can guess that we need some credentials to call method. You can see the configuration; it says clientCredentialsType="Windows" and security mode is Message, generally with wsHttpBinding these are the typical settings.

As we are using Windows as credential type, we need to provide credentials to use WCF serverice out of box. Once this done you just need to pass user and password in ClientCredentials just like bellow

Baroda Developers Conference

2009-11-21T09:36:00.000-08:00

Hello All,

Event Baroda Developer Conference was held on Saturday, November 21, 2009 at Dr. I.G. Patel Seminar Hall Vadodara.

Links: Baroda Mega Developers Conference; Baroda Developers Conference [Dev-Con]

I recently gave presentation at a session titled as "Features of C# 3.0" followed by Probjots session "Introducing LINQ" & "VS 2010 & .Net 4.0" and "MOSS 2007" by Bhavin Gajjar.

It was my first experience to give a presentation. There were students who were part of Microsoft Student Partner program with sound knowledge in Microsoft .Net Technology.

Here are few snaps from conference.

[Attending one students' question on Partial Methods]

[Me with Probjot and students]

[Attendees]

I want to congratulate all the attendees for being part of such a knowledge sharing conference and taking active part in it.They came from different territories of all over India. I really appreciate their interest. Also I have demo project which I have used during my presentation to get this send me an email.

I am very much thankful of Jacob Sebastian who promoted me for this event and Prakher Mehta who was the organizer and inviter of BUG [Baroda User Group]

Rolebase page access and rulebase operation access

2009-10-14T21:49:00.001-07:00

Hi Again,

This is typical scenario where programmer done want to allow specific user to visit specific page due to functionality which needs to be secure based on user types. The task like managing users should not accessed by a normal user. So we need security based on user types, more precisely we need Authorization. Once user passed thru authentication it is not Authorization who decide the access of current logged user to perform some task.

Before introductions of ASP.NET Rolebase providers, people used to check on each page for the role, and if it does not have that role then redirection process, here all data related to user role kept in session.

This functionality is much more simpler after introduction of Rolebase provider, we just need to define roles and access to that roles. We can restrict users based on either role or userid itself, its depend how the application needs the functionality. This is for particular page, now what if I need to restrict user at operation level? Mean I don't allow Account user to manage users personal details, he just need to play with user's account, he does not need to update personal details of user. Here we can use Rolebase provider to check whether logged in user have rights to perform that operation or not.

Rolebase page Access: After setting roles and mapping, you just need to add few settings into configuration file which rolebase provider will use to perform authorization. Typical example of such web.config is as following.

Lets understand the setting.

location tag in which you have to specify path of resource. If path is directory then the authorization will consider on all the pages inside that directory.
authorization tag will contains the allow or deny user/roles listing.
allow tag contains the roles attribute, in which you have to put role name. So you are allowing user having SiteAdmin to access ManageUser page. In the same way if you write deny roles then it will deny that particular role to access ManageUser page.
deny tag contains roles or user. In typical setting we are putting selected roles/users in allow list and for rest we kept as deny, so in deny you may always find * which means all user or all roles.

Typically we have more then one configuration files kept in different-different directories to manage folder separately.

Now let's see how we can implement operation level security using Rulebase provider. Microsoft Enterprise Library Security Application Block helps developers implement common authorization-related functionality in their applications. We just need to set some configuration setting using which you can identify the operation level access. Following is the typical configuration to implement rulebase provider.

You can see the how rule has been added here along with expression. You can add new rule by adding name and expression, expression is simple string which contains set of Role name and expression. There are list of more expression you can find bellow. First lets try to understand EditPersonalInfo rule, it has two role SiteAdmin or Superuser or User, so all user having these roles can perform EditPersionInfo operation.

Rule Expression can contains I, R, AND, OR, NOT, (, ), ?, *.

I: It will authorize to identity which is supplied with I
- expresson="I:Imran" will allow a user with identity Imran
R: It will authorize to role which is supplied with R
Rest will be operator you can use at any time
- expression="((R:Superuser OR R:AccountAdmin) AND (NOT R:SiteAdmin))"

Now this is all about configuring rules. Will see how to apply these rules in our coding.

Just two lines of code to know weather user is authorize to do that action or not.

SQL Challenge - Find second highest salary by department

2009-10-13T23:37:00.000-07:00

Hello All,

I am starting this new thread called SQL Challenges, which will have SQL Challenge for beginners. I hope your all like that and participate also.

Jacob Sebastian, had already started posting challenges, I would like you to participate into challenge, may be you can get gift or rewards.

There are some rules and regulation which you have to read before posting any reply, it's very simple not a big deal. So first challenge is out there, to finding out second highest salary by department, please visit this link for more details. You can find scripts to generate data too.

Hope you will have great time to solving and most important thing is learning; you will learn lot not only from question also from the best answer posted for particular challenge.

Core Service - Extensible Output Caching

2009-10-11T02:03:00.000-07:00

Output caching is one of the major factor to load your page more faster. up to now ASP.NET allow developer to store generated output of page, control and HTTP request into memory to used further request.

ASP.NET 4.0 provides the mechanism to let developer handle output cache by creating your own custom output-cache provider and manage the persistency of HTML content. For doing this you just need to create class which derives from System.Web.Caching.OutputCacheProvider type and add it to your caching section of web.config. The default provider is AspNetInternalProvider.

In addition, you can choose different provider for different pages! There are two way to do this.

First you need to override one new method in Global.asax called GetOutputCacheProviderName which helps you to select output cache provider.

Adding code at request level is like adding more work to do, the easiest way is to select output-cache provider is to set value of attribute providerName which is part of OutputCache page or control directive.

Topic: ASP.NET 4.0 and Visual Studio 2010 Web Development Beta 2 Overview

Core Service – Web.Config file Minification

2009-10-10T21:05:00.001-07:00

The configuration file is very important for each web application, each web application will have one master web.config file which contains all the setting that a simple web application needs, on top of it we have machine.config, there always be single machine.config file.

Now typical web.conifg will have lots of section and sub-section which are common for all the application, like AJAX related stuff, IIS integration and many more, what 4.0 does is it moved common setting from web.config to machine.confg, this means now your web.config file in ASP.NET 4.0 either empty or contains following lines.

Topic: ASP.NET 4.0 and Visual Studio 2010 Web Development Beta 2 Overview

Overview of new features in windows 7 - MTD Session

2009-10-06T06:21:00.000-07:00

Hello All,

This is my first post on Windows 7, I have attended the event Microsoft Community TechDays on 3rd October 2009 in Ahmedabad having one of the session on cool features of Windows 7, that had been presented by Vinod Kumar Microsoft Evangelist, who is known for his famous SQL site http://extremeexperts.com/. Who basically expert in SQL Server but did wonderful presentation with only one slide and tones of tips and tricks by Demo, I enjoyed the session lots.

I am listing some cool features which I like the most in windows 7 here, this does not mean that features rest feature I don't like but may be I need to explore windows 7 more and more as there are lots of features that been added to windows 7.

[Jacob Sebastian, Imran Bhadelia, Vinod Kumar]

Jump List

The Jump List feature is designed to provide you with quick access to the documents and tasks associated with your applications. You can think of Jump Lists like little application-specific Start menus. Jump Lists can be found on the application icons that appear on the Taskbar when an application is running or on the Start menu in the recently opened programs section. Jump Lists can also be found on the icons of applications that have been specifically pinned to the Taskbar or the Start menu.

For developer the JumpListManager class provides an abstraction of the application jump list, including facilities to manipulate custom destinations, user tasks, recent/frequent lists and items removed by the user.

VHD [Virtual Hard Disk]

I like this feature the most, VHDs are widely used as storehouses for hard disk images you intend to deploy out to clients. For example, you can keep different images, for different types of users, in the form of separate VHDs and then just deploy the ones you need to whomever they need to go to. Although VHD is closely intertwined with virtualization, it's also being widely used as a stand-alone tool because Windows 7 adds support for Native VHD, which means you can use it without virtualization in place.

Global Keyboard shortcuts

I love to use keyboard as much as I can, windows 7 have added lots of shortcuts to it, I am listing few here.

Win+Space operates as a keyboard shortcut for Aero Peek.
Win+Up and Win+Down are new shortcuts for Maximize and Restore/Minimize.
Win+Shift+Up vertically maximizes the current window
Win+Left and Win+Right snap the current window to the left or right half of the current display; successive keypresses will move the window to other monitors in a multi-monitor configuration.
Win+Shift+Left and Win+Shift+Right move the current window to the left or right display.
Win+ + and Win+ − (minus sign) zoom the desktop in and out.
Win+Home operates as a keyboard shortcut for Aero Shake.
Win+P shows an "external display options" selector that gives the user the choice of showing the desktop on only the computer's screen, only the external display, on both at the same time (mirroring), or on both displays with independent desktops (extending).

Direct Access

Traditionally, remote users connect to internal network resources with a Virtual Private Network (VPN). However, using a VPN can be cumbersome for users because it requires several steps, and several seconds (or even minutes), for authentication to occur. Windows 7, together with Windows Server 2008 R2, introduces DirectAccess, a new solution that enables users to have the same experience working remotely as they would working in the office. Taking advantage of technologies such as IPv6 and IPSec, DirectAccess provides remote computers with automatic, seamless access to the internal network across the Internet without connecting to a Virtual Private Network (VPN), while providing secure and flexible network infrastructure for enterprises.

Taskbar APIs for developer

The IMClient sample demonstrates how taskbar overlay icons and taskbar progress bars can light up an application’s taskbar button instead of relying on an additional dialog or on an icon in the system notification area (tray).

Aero Shake

Aero Shake allows users to clear up any clutter on their screen by shaking (dragging back and forth) a window of their choice with the mouse. All other windows will minimize, while the window the user shook stays active on the screen. When the window is shaken again, they are all restored, similar to desktop preview.

Problem Steps Recorder

A very handy tool to record steps which produce the problem, this is very useful if you belong to Quality Assurance. It gives you details of every operation that you had done along with image and description, and again it requires very less space as its highly compact. The Problem Steps Recorder creates a .MHT file (a type of HTML document that includes images in a single file) compressed in a zip archive. The IT professional can open the .MHT file, view screenshots and get an exact description of the user’s actions. It helps overcome language barriers, allowing IT professionals to diagnose problems regardless of language differences

Resource Monitor

Before I was using process monitor, windows 7 have introduced resource monitor, which is way ahead from process monitor, it gives you all the information regarding CPU, Memory, Disk and Network.

More Advance Calculator

New functionality allows the user to not only calculate in the Standard and Scientific modes, but also in Programmer and Statistics modes. And that’s not all! Ever need conversion formulas for temperature, weight, area, or time? Finding the unit conversion option makes it a snap and takes all the work out of the user’s hands.There are even templates for gas mileage, lease estimations, and mortgage estimations.

Aero Peek Your Desktop

A lesser-known versatile tool introduced with Windows 7 is the Aero Peek. Just click the rectangle in the lower right hand corner of the task bar for quick access to your desktop. The keyboard shortcut Window Key + Space performs the same function.

Repeater with Paging and Sorting Features

2009-07-15T20:20:00.001-07:00

Hi all,

We all know our pages need to be created dynamic, .NET provides some good inbuilt controls which does same thing specifically framework 2.0 included lots of handy controls to build you page quickly

I usually pick the Repeater control, to render simple or complex table, why because its very simple and main reason is its faster and light weighted. There are limitation of Repeater, like it does not have inbuilt functionality for Paging and Sorting.

We can add the functionality of Paging and Sorting by our own, I wrote an article on Extended Repeater, having Sorting and Paging support with very less effort. It uses PagedDataSource I am sure its very new to you! But it’s now new it was there as in framework 1.1!

You can find the article here, I have explained all important code logic and also you can download the sample code there.

Create your own shortcut in SQL Management Studio 2008

2009-07-02T07:03:00.001-07:00

Hi All,

Shortcut is good way to increase the speed of development and work. SQL Server Management Studio 2008 have numerous shortcuts.

We are writing various SQL statement, few statements are common like, SELECT * FROM [TABLE_NAME] which we are using very frequent. its always tedious job to write SELECT * FROM statement, can’t we create shortcut for that? Yes we can. Here is the steps to create your own shortcut with screenshot may be it helps you to increase productivity.

Step 1: Find the Keyboard setting [Tools – Options – Keyboard]

Step 2: Pick the available Shortcut [Query Shortcuts]

Here you can see the default query shortcuts. Find the available and create your own.

Lets create one shortcut for SELECT Statement

Press OK, you are done with your first shortcut. Before we use the shortcut and it get applies we need to restart IDE so our shortcut will get effected.

After restarting IDE, in Query write the table name, select it and apply your shortcut [Ctrl+f1].

You can see it works like SELECT * FROM EmpMaster. Now let’s apply WHERE clause and see if its works or not?

It’s working perfectly. Use shortcuts be more productive.

Get query string value using JavaScript

2009-06-30T14:40:00.001-07:00

Here is the JavaScript function getQuerystring which finds the key form query string and returns the value.

/*
* <summary>
* Get the querystring value
* </summary>
* <param name="key">A string contains the querystring key</param>
* <param name="defaultVal">Object which get returns when there is not key</param>
**/
function getQuerystring(key, defaultVal) {
    if (defaultVal == null) {
        defaultVal = "";
    }
    key = key.replace(/[\[]/, "\\\[").replace(/[\]]/, "\\\]");
    var regex = new RegExp("[\\?&]" + key + "=([^&#]*)");
    var qs = regex.exec(window.location.href);
    if (qs == null) {
        return defaultVal;
    }
    else {
        return qs[1];
    } 
}

Register for PHP Developers Day

2009-06-22T07:11:00.001-07:00

Microsoft invites you to this exclusive session on Microsoft InterOp initiatives tailored for open source developers to create cutting-edge business applications.

Title

Level

Speaker

Details

1.	Build Mission Critical Applications on the Microsoft Platform using Eclipse

300

Nahas Mohammed, Technology Advisor, Microsoft

Microsoft has delivered multiple technologies that focus on interoperability with non-Microsoft and Open Source technologies. Learn how to use Eclipse tools today to build Silverlight applications that run on PCs and Macs, how to work in a cross-platform environment and yet integrate your solution with your designer team. Also get to know about Microsoft's commitment to openness with the Azure Services Platform.

2.	jQuery - the write less do more javascript library

300

Deepak Gulati, Lead Architect, Cricinfo.com

jQuery has gained tremendous popularity in little over two years. It aims to allow web developers to write clear, concise code that cleanly separates the behavior of a page from its design without having them fret over details of cross-browser Javascript development. With its formal inclusion into Microsoft's Ajax stack, it is bound to become an important tool in an ASP.NET Web
Developer's toolbox.
We'll begin with a whirlwind tour of some advanced features of Javascript and then move on to using jQuery for:

-	Efficient DOM traversal and manipulation
-	Using a unified event handling mechanism across browsers
-	Increasing visual and functional appeal of your web-pages with special effects and plugins

3.	MS SQL Business Intelligence with mySQL

300

Praveen Srivatsa, Director, Asthrasoft

Have your data residing on mySQL but want to leverage MS SQL server capabilities to build Business Intelligence solutions? Then this is the right session for you. This session looks at leveraging your existing investments in mySQL and leveraging the Reporting and Analysis Services from MS SQL server to extract data out from your mySQL data store to build meaningful dashboards. It looks at how we can integrate SQL Reporting Services and use SSIS to harvest the data from mySQL. It also looks at how we can replicate or sync data between MS SQL Server and mySQL to be able to share the relevant data across these databases.

4.	Trouble Ahead? Know Your Project Warning Signs! How Successful Leaders Recognize and Deal with Project Warning Signs

Sanjay Dugar, instructor, ESI International

This session is run by ESI and provides detailed guidance on conducting project health checks, what warning signs to look for, how to find them and finally, when to pull the plug on a project. For more than 25 years, ESI International has helped many of the world's most successful organizations-including Fortune 1000 companies and nearly every major agency of the United States federal government-align strategies, build talent and achieve organizational goals. To date, ESI has helped more than 850,000 technical and specialized professionals around the world improve the way they manage their projects, contracts, requirements and vendor relationships.

Long word breaks the UI

2009-06-13T16:24:00.001-07:00

Hi All,

Working with long word into Web application some times break the UI. There always be a question for How to break long words?? As a long word without space kills your user interface.

I found the reason, in general when you system is tested by QA first thing he is going to break if you don’t limit the size and then it try to break UI with adding a loooooong space less word :)

There can be lots of other solutions, like create function which finds the long word and break it out. But I like is Regx, yes the regular expression is very optimum, but you have to learn them which is not like eating piece of cake :)

Following is the Regx which validate the text box and allow user to add 35 character long word although it seems to be not possible :)

<asp:RegularExpressionValidator ID="regNoLongWords" runat="server" ControlToValidate="txtText"
    ErrorMessage="Word is too long" Display="None" 
    ValidationExpression="(?!.*?\S{36,}).*"></asp:RegularExpressionValidator>

Have fun with Regx !!!

Tech.Ed India 2009

2009-06-12T22:17:00.001-07:00

Its a great pleasure to make announcement that Tech.Ed 2009 its now in Ahmedabad, its FREE event and you should go and attend it. If you missed TechEd Indian 2009 at Hydrabad then you can now attend it in Ahmedabad, Gujarat, India on June 20, 2009 Saturday at Rock Regency.

You may get change to meet/talk to two MVPs Pinal Dave and Jacob Sebastian, who will also going to attend this event. If you are interested then register here it’s based on First Come First Serve.

Best way to hiding Telerik Grid Column

2009-06-08T13:26:00.001-07:00

Hi All, I was just looking into list of function while applying some logic for show/hide column of Telerik it provides two methods to do so.

public GridColumn FindByUniqueName(string UniqueName);
public GridColumn FindByUniqueNameSafe(string UniqueName);

As name suggest first method is not safe, it can throw GridExceptions if no column is found, where second one is returning null if no column is found. Along with these tow method, it have one property name UniqueName; this property helps FindByUniqueName and FindByUniqueNameSafe to find the column. So now we don’t need to remember the column id also we can now easily change the sequence of column as they are not referring with unique name.

<telerik:GridTemplateColumn UniqueName="Clients" HeaderText="Clients">

And server side write following code.

GridColumn gridColumn = dgTest.Columns.FindByUniqueNameSafe("Clients");
if (gridColumn != null)
    gridColumn.Visible = false;

Viewstate in dynamic Control

2009-06-03T09:53:00.001-07:00

Hi All,

There is general problem to having issue with ViewState in dynamic control.

I have posted one article Code Project you can find it here.

Using let in LINQ to Objects – Performance killer if used wrong way

2009-05-27T06:53:00.001-07:00

C# 3.0 LINQ has one more hidden and powerful feature; which provides you to store result of sub-expression in order to use subsequence clause. You can achieve this with the help of let keyword. The variable created using let is readonly; once initialized it can’t use to store another value only good this is it can be queried.

Let’s see this with example. We have employees details in text file delimited my ‘:’, also each employee have it’s own details separated by ‘,’.

string strEmployees = "1, John, Methew:2, Nick, Althoff:3, David, Oliver:4, Sam, Peterson";

Lets write query to grab all the employee details.

string strEmployees = "1, John, Methew:2, Nick, Althoff:3, David, Oliver:4, Sam, Peterson";

//Split with :
var query = from empData in strEmployees.Split(':')
            select empData;

//Split with ,
foreach (var q in query)
{
    var e = q.Split(',');
    Console.WriteLine("Id - {0}, First Name - {1}, Last Name - {2}",
        e[0], e[1], e[2]);
}

As you can see we have to write two different logic to split one more time employee details, now let’s use let keyword and make coding easy.

string strEmployees = "1, John, Methew:2, Nick, Althoff:3, David, Oliver:4, Sam, Peterson";

var query = from empData in strEmployees.Split(':')
            let emp = empData.Split(',')
            select new { Id = emp[0], FName = emp[1], LName = emp[2] };

foreach (var q in query)
{
    Console.WriteLine("Id - {0}, First Name - {1}, Last Name - {2}",
        q.Id, q.FName, q.LName);
}

In both query output will be same.

emp is intermediate enumerable type which we are using in next line! This is very simple example, now what compiler treats the code above? Compiler will create one sub-query that returns the anonymous type composed of the original value along with new value specified by the let.

As its creating sub-query if you write bunch of let statements, it will kill your performance. If its implemented in proper way let is very good option to go with, the scenario where you need some function which operates on your select clause more then 2-3 times, you can create let variable and use them into your select which makes your faster.

static void SummOfferNoLet()
{
    var q = from c in Products
            where SumOffers(c) < 10000 && SumOffers(c) > 1000
            select c;
    int count = q.Count();
}
static void SummOfferWithLet()
{
    var q = from c in Products
            let offerValue = SumOffers(c)
            where offerValue < 10000 && offerValue > 100
            select c;
    int count = q.Count();
}

In this case SummOfferWithLet will faster as you can see SummOfferNoLet we need to call SumOffers twice.

Conclusion: Using let is powerful but if you used wrong way then it will kill the performance.

Issues with Web.config in IIS 7 and Modules (in Vista)

2009-05-25T18:10:00.001-07:00

A simple web application runs fine on internal web server, but the time we put it on IIS7 specially in Windows Vista, its start giving configuration error, first and foremost is issue with Modules.

This configuration section cannot be used at this path. This happens when the section is locked at a parent level. Locking is either by default (overrideModeDefault="Deny"), or set explicitly by a location tag with overrideMode="Deny" or the legacy allowOverride="false".

And its points to <handlers> section under <system.webServer> section. The issue related to IIS don’t have ASP.NET installed. You can check your Windows feature, although you have installed IIS7 and compatibility for IIS6, ASP.NET is not getting installed automatically. Here is the Windows feature should look like as in following image.

You can find this window from Control Panel –> Programs and Features –> Turn Windows features on or off [Left panel]

If you have ASP.NET installed on your IIS 7.0 then you have to change the configuration from applicationHost.config file, which resides in %windir%\system32\inetsrv\config\applicationHost.config. You can find the entry for handlers and it has value Deny for property overrideModeDefault, change it to Allow.

While saving file I am pretty much sure that it asks for Administrator account although your role is Administrators as you are not owner of that file you can’t make change to file, so solution for this is login as Administrator and do the changes. For vista Administrator is not active for login so find my post which help you to login as Administrator.

How to login as Administrator in Windows Vista

2009-05-23T23:28:00.001-07:00

Hi All,

In working with Visa, you always get Alert saying “You don’t have permission to access this folder, click continue to get access”, or “Windows needs your permission to continue” or “Destination Folder Access Denied” or due to security you are not able to save file or change who owned by System…. Lots more. Although you have Administrative privileges still its says sometime “You should have administrative permission”. Or if a program needs Admin permission then you can run that application using “Run as Administrator”!!!!

So we need to do login using Administrator account, but the question is from where?

In Vista, the Administrator (or an administrator) is no longer the most trusted object in the operating system. Yes this is to "ostensibly" protect the system, and is part of a general concept of protecting the integrity of the system. The Administration is not activated and you don’t find any User Interface [Up to now, I didn’t fine] which make it active!!! Does it means you can’t make it Active? NO.

To make it active, you have to run command prompt with Administrator permission. Go to Start –> All Programs –> Accessories –> Command Prompt [right click and RUN AS ADMINISTRATOR]

Write following commands to make Administrator active and set the password.

First command will make Administrator account active and another will set yourpassword as Administration account password. Last command Exit.

Now, reboot or switch user or logoff from current user; you can see it will ask for Administrator account password.

USE AT YOUR OWN RISK.

This application has failed to start because the application configuration is incorrect – Solution

2009-05-23T09:26:00.001-07:00

I have migrated Vista Home to Vista Premium and my SQL Server and Visual Studio 2008 was not able to start and giving me error ‘This application has failed to start because the application configuration is incorrect, the application has failed to start because its side-by-side configuration is incorrect’. I then check the Event Viewer and find some Dependent Assembly were missing.

Activation context generation failed for "C:\Program Files\Microsoft Visual Studio 9.0\Common7\IDE\PrivateAssemblies\LanguagePackage.dll". Dependent Assembly Microsoft.VC80.CRT,processorArchitecture="x86",publicKeyToken="1fc8b3b9a1e18e3b",type="win32",version="8.0.50727.1833" could not be found. Please use sxstrace.exe for detailed diagnosis.

Solution: If you are using VS2005 then download vcredist_x86.exe, and for 2008 download vcredist_x86.exe. No need to do any registry entry or any manifest file.

User Group Meeting [18-Apr-09]

2009-04-17T00:18:00.001-07:00

Its time to announce the user group meeting for Ahmedabad SQLServer UserGroup for the month of April.

The main focus of the meeting will be XML features of SQL Server 2008. You can read more on http://ahmedabad.sqlpass.org/

I would like you to join and gain lots of knowledge and also there will be QA session where you can ask any question related to topic or SQL Server

Hope to see many of you tomorrow!!!

Enum in JavaScript

2009-04-02T06:31:00.001-07:00

We are using enum in server side scripting language, recently I come across requirement where I have to write lots of if-else if clause, then I found the interesting thing which is enum.

Lets see how we can declare enum.

var Technology = 
{ 
    Microsoft: 0,
    PHP: 1,
    ROR: 2,
    Java: 3
}

Minor change in declaration, now lets see how we can use enum.

function Show(tech) {

    var msg = 'Welcome to the world of {0}';
    switch (Number(tech)) {
        case Technology.Microsoft:
            alert(String.format(msg, 'Microsoft'));
            break;
        case Technology.PHP:
            alert( String.format(msg, 'PHP') );
            break;
        case Technology.ROR:
            alert(String.format(msg, 'ROR') );
            break;
    }

}


//And here is the function call
Show(0);
Show(Technology.PHP);
Show(Technology.Microsoft);
Show(2);

Anonymous Types in C# 3.0

2009-03-27T05:14:00.001-07:00

We all know about Abstract Type, generally we are creating Class which are Abstract Type, A Class has name assigned with it. Anonymous Type are Class without specifying the name to it. You can create Anonymous class by using new operator. Consider the following example.

class AnonymousType
{
    public string Name { get; set; }
    public int Age { get; set; }
    public string Country { get; set; }
}
.
.
.
AnonymousType a1 = new AnonymousType { Name = "Marco" };
var a2 = new AnonymousType { Name = "Paolo" };
var a3 = new { Name = "Tom", Age = 31 };
var a4 = new { a2.Name, a2.Age };
var a5 = new { a1.Name, a1.Country };
var a6 = new { a1.Country, a1.Name };

The variables a1 and a2 are of the AnonymousType, but the type of variables a3, a4, a5, and a6 cannot be inferred type, see more on Local Type Inference. The var keyword get the type based on assigned expression which must with new keyword and without a type specified.

The variables a3 and a4 are of the same anonymous type because they have the same fields and properties. Even if a5 and a6 have the same properties (type and name), they are in a different order, and that is enough for the compiler to create two different anonymous types.

You can use anonymous type in array initializer too, lets see and example.

var ints = new[] { 1, 2, 3, 4 };
var arr1 = new[] {
          new AnonymousType { Name = "Marco", Country = "Italy" },
          new AnonymousType { Name = "Tom", Country = "USA" },
          new AnonymousType { Name = "Paolo", Country = "Italy" }};
var arr2 = new[] {
          new { Name = "Marco", Sports = new[] { "Tennis", "Spinning"} },
          new { Name = "Tom", Sports = new[] { "Rugby", "Squash", "Baseball" } },
          new { Name = "Paolo", Sports = new[] { "Skateboard", "Windsurf" } }};

While ints is an array of int and arr1 is an array of AnonymousType, arr2 is an array of anonymous types, each containing a string (Name) and an array of strings (Sports). You do not see a type in the arr2 definition because all types are inferred from the initialization expression. Once again, note that the arr2 assignment is a single expression, which could be embedded in another one.

You can read more features from my older post, Automatic Properties, and Object-Collection Initialization, Local Type Inference and Partial Methods.

Local Type Inference in C# 3.0

2009-03-25T04:20:00.001-07:00

There are list of new features added in C# 3.0, I already cover Automatic Properties, and Object-Collection Initialization and Partial Methods in my older posts, here one more new feature which allow you to write more relaxed code. In another work you can define variable and use them without worrying about too much about their type, leaving it to the compiler to determine the correct type of a variable by inferring it from the expression assigned to the variable itself.

The price for using type inference might be less explicit code against the types you want to use, but in our opinion, this feature simplifies code maintenance of local variables where explicit type declaration is not particularly meaningful.

This might seem to be equivalent to defining a variable of type object, but it is not. The following code shows you that an object type requires the boxing of a value type (see b declaration), and in any case it requires a cast operation when you want to operate with the specific type (see d assignment):

var a = 2;       // a is declared as int
object b = 2;    // Boxing an int into an object
int c = a;       // No cast, no unboxing
int d = (int) b; // Cast is required, an unboxing is done

C# 3.0 offers type inference that allows you to define a variable by using the var keyword instead of a specific type. When var is used, the compiler infers the type from the expression used to initialize the variable.

The var keyword calls to mind the Component Object Model (COM) type VARIANT, which was used pervasively in Visual Basic 6.0, but in reality it is absolutely different because it is a type-safe declaration. The following code shows some examples of valid uses of var: x, y, and r are double types; d and w are decimal; s and p are string; and l is an int. Please note that the constant 2.3 defines the type inferred by three variables, and the default keyword is a typed null that infers the correct type to p.

public void ValidUse(decimal d)
{
    var x = 2.3; // double
    var y = x; // double
    var r = x / y; // double
    var s = "sample"; // string
    var l = s.Length; // int
    var w = d; // decimal
    var p = default(string); // string
}

The next sample shows some cases in which the var keyword is not allowed:

class VarDemo
{
    // invalid token 'var' in class, struct or interface member declaration
    var k = 0;
    // type expected in parameter list
    public void InvalidUseParameter(var x) { }
    // type expected in result type declaration
    public var InvalidUseResult()
    {
        return 2;
    }
    public void InvalidUseLocal()
    {
        var x; // Syntax error, '=' expected
        var y = null; // Cannot infer local variable type from 'null'
    }
    // …
}

The k type can be inferred by the constant initializer, but var is not allowed on type members. The result type of InvalidUseResult could be inferred by the internal return statement, but even this syntax is not allowed .

Partial Methods in C# 3.0

2009-03-25T00:31:00.001-07:00

In C# 2.0 Partial Class has been added, which was I personally believe very good features to work in multi-developer environment.

One more new feature added in C# 3.0; Partial Method. I already talked about Automatic Properties, and Object-Collection Initialization which also introduced in C# 3.0. Partial Method is a method which must reside [only signature] into Partial Type [Partial Class] and if define somewhere then will get executed. This basically a rule created by one, if other want to implement then go ahead or leave it blank. I can compare it with Interface method; although its major difference between Interface method and Partial method. In Interface method if you does not implement then the type which implement that interface MUST be abstract; but in the case of Partial Method, its not abstract but its Partial.

There are few rules if you want to work with Partial Methods:

A method must be declared within Partial Class or Partial Structure
A method cannot have access modifiers. [virtual, abstract, new, sealed...]. They are always private
A method must return void
A method cannot have out parameter
A method definition hast to end with ';'

Here is the simple example of Partial Methods

partial class PartialMethods
{
    partial void DoSomeWork();
}

If you build with this code, it will work fine although we haven't write body of this function. If you see the Manifest you wont find this method anywhere. The only constructor will part of PartialMethods class.

Now let me write body for the method and check manifest again

partial class PartialMethods
{
    partial void DoSomeWork();
}

public partial class PartialMethods
{
    partial void DoSomeWork()
    {
        //Do your work here
    }
}

Now we can see the method, this class is not full class but as partial methods are private, you cant not access from outside, you have to call within that class. Partial method allow developer to create rule which can be implemented later but only once.

Object and Collection Initialization in C# 3.0

2009-03-14T00:24:00.001-07:00

My last post I speak about Automatic Properties, and how we can use them. Here we will discuss the Object and Collection Initialization in C# 3.0. In general we are do initialize our property either inside constructor [standard method] or by calling some methods or assigning value directly to public property. Let's see how.

public class Test
{

    public class InitializeTest
    {
        public int Id { get; private set; }
        public string Name { get; private set; }

        public InitializeTest()
        {

        }

        //Initialize using constructor
        public InitializeTest(int intId, string strName)
        {
            Id = intId;
            Name = strName;
        }

        //Initialize using method
        public void SetId(int intId)
        {
            Id = intId;
        }
    }

    static void Start()
    {
        //Initialize using constructor
        InitializeTest objInitializeTest1 = new InitializeTest(1, "a");

        //Initialize using method
        InitializeTest objInitializeTest2 = new InitializeTest();
        objInitializeTest2.SetId(1);
    }
}

Lets talk about initialize using constructor, we have two constructor, one is default and another is accepting two arguments. so far so good. Lets say I have added new property into my class, then? have to create new overloaded constructor? or modify two argument constructor with three which will raise few more errors!!! First one will be better option.

public char Sex { get; set; }

//Initialize using constructor
public InitializeTest(int intId, string strName) : this(intId, strName, 'M') { }

//Initialize using constructor
public InitializeTest(int intId, string strName, char cSex)
{
    Id = intId;
    Name = strName;
    Sex = cSex;
}

Now to avoid this lets see what is in Object Initialization provided by C# 3.0. We can simply use single argument constructor to initialize the member of class, lets add one more property to class name Birthdate.

public class InitializeTest
{
    public int Id { get; set; }
    public string Name { get; set; }
    public char Sex { get; set; }
    public DateTime Birthdate { get; set; }
    .
    .
    .
    .
}

You may notice here that I have removed private scope why? I will explain it later.

static void Start()
{
    InitializeTest objInitializeTest3 = new InitializeTest() { Id = 1, Birthdate = DateTime.Now, Name = "Name", Sex = 'M' };
}

That's it!!! initialize the value of property right after constructor inside the curly braces. You can also assign few or complete list. Now if we make Id property private we can't use here [outside of the class] that is the reason for removing private to get accessor. How it works?

The syntaxes used to initialize an object (standard and object initializers) are equivalent after code is compiled. Object initializer syntax produces a call to a constructor for the specified type (either a reference or value type): this is the default constructor whenever you do not place a parenthesis between the type name and the open bracket. If that constructor makes assignments to the member fields successively initialized, the compiler still performs that work, although the assignment might not be used. An object initializer does not have an additional cost if the called constructor of the initialized type is empty

This can be done on parameterize constructor as well.

We seen object initialization, same was we can achieve collection initialization. Let's see how. First lets add one generic collection to out class and then will do initialization.

public class InitializeTest
{
    .
    .
    public List<string> FamilyMembers { get; set; }
    .
    .
}
.
.
static void Start()
{
    InitializeTest objInitializeTest4 = 
        new InitializeTest() { FamilyMembers = { "First", "Second", "Third" } };
}
.
.

Its really easy and we have eliminated quite a bit of typing.

Automatic Properties in C# 3.0

2009-03-13T23:28:00.001-07:00

Automatic properties are introduced in 3.0 of C#. Using automatic properties you can save your lots of time and typing.

Up to now we were writing following code to create single property.

public class PropertyTest
{
    private string _strTest;

    public string strTest
    {
        get { return _strTest; }
        set { _strTest = value; }
    }
}

Now look at the automatic properties bellow.

public class PropertyTest
{
    public string strTest { get; set; }
}

Only single line of code!!!
We can even restrict the get and set property, like we need set property to be private and get property to be public; yes we can do that too.

public class PropertyTest
{
    public string strTest { get; private set; }
}

Although its time saver there is few limitation for this, lets list out those limitations.

Automatically implemented properties must define both get and set accessors, if not have to make them abstract.

//Gives you error
public class PropertyTest
{
    public string strTest { get; }
}

//Works fine
abstract public class PropertyTest
{
    abstract public string strTest { get; }
}

You can't initialize them in declaration, although you can do it into Constructor

public class PropertyTest
{
    public string strTest { get; set; }
    
    public PropertyTest()
    {
        strTest = "Test String";
    }
}

Free ASP.NET MVC Tutorial

2009-03-11T22:04:00.001-07:00

The announcement made by Scoot Guthrie on 11-March-2009 that you can now download the tutorial for MVC.

The free ASP.NET MVC Tutorial having following points covered along with images.

File->New Project
Creating the Database
Building the Model
Controllers and Views
Create, Update, Delete Form Scenarios ViewData and ViewModel
Partials and Master Pages
Paging Support
Authentication and Authorization
AJAX Enabling RSVPs Accepts
Integrating an AJAX Map
Unit Testing

You can find the original post by ScootGu from here, and the PDF from here.

A sample application for ASP.NET MVC you can find it from Codeplex.

Sequence contains no element - LINQ

2009-02-24T04:42:00.001-08:00

Recently using Aggregate function in LINQ I come across sequence contains no element error. After checking I found the list on which I am calling Aggregate function does not have any element!!!

Problem:
ERROR : Sequence contains no element, while using Aggregate function in LINQ

Lets see with example.

I have created AssignMe function which returns the collection of string, here is the function body.

private static string[] AssignMe()
{
    return new string[] { };
}

For generating error AssignMe is returning nothing, now lets apply Aggregate function on this

string[] sList;
sList = AssignMe();
Console.Write(sList.Aggregate((first, second) => first + second));

This will throw InvalidOperationException => "Sequence contains no elements".

Lets change the AssignMe function little bit.

private static string[] AssignMe()
{
    return new string[] { "NoException" };
}

This will work perfectly, and gives you output as NoException, don't get confused with NoException, Its returning result.

Solution:

We should check the item Count before applying Aggregate function, as we seen it's working well for single element. Lets put back our original AssignMe function and change the calling method.

string[] sList;
sList = AssignMe();

if (sList.Count() > 0)
    Console.Write(sList.Aggregate((first, second) => first + second));

Working fine without an error :)

Conclusion:
While using Aggregate function or any other function like lamda expression or delegate; which accept argument then its better to check the Count of collection before applying such function.

File Upload not working with update panel

2009-02-19T05:11:00.000-08:00

I was having problem while using File upload control which is inside the update panel and which was placed in user control. While doing post-back the value of PostedFile was blank, although page was properly valid.

Then I checked the Form property of Request object, the file upload control was missing in the AllKeys collection

We all know that if you want file uploads the form encode must be multipart/form-data. This is the reason why File Upload is not working properly inside Update Panel, lets understand this with following example.

Problem:

File upload is not working with update panel + asp.net

You are having two controls which needs to get display after one-another or post-back, first control does not have File upload and Second control does. Things to notice here is form tag will be reside either in ASPX page or Master page not in UserControl; and our File Upload is inside user control. Now when we load first control which does not have File Upload so the form will not encoded with multipart/form-data, now when you load second control which has the File Upload hence fort encode must be multipart/form-data, which is unfortunately not changing due to Update Panel.

Solution:

In problem definition we come to know that form must be encoded with multipart/form-data if we want to upload the file; solution is very simple, we just need to change encoded attribute of form with following single line!!!

Page.Form.Attributes.Add("enctype", "multipart/form-data");

String Concatenation in SQL Group By clause

2008-12-16T23:39:00.001-08:00

I got one problem in Ahmedabad SQLServer UserGroup.

The problem was something like... there are grouped data and requirement was making sum of string collection, means concatenation of string which are in the same group. Here is the question along with solutionSource Table

Field1     Field2
---------- ----------
Group 1    Member 1
Group 1    Member 2
Group 1    Member 3
Group 2    Member 1
Group 2    Member 2
Group 3    Member 1
Group 3    Member 2

Need output as

Field1     Field2
---------- ----------------------------
Group 1    Member 1,Member 2,Member 3
Group 2    Member 1,Member 2
Group 3    Member 1,Member 2

Solution:

SET NOCOUNT ON

--Creating Tables
DECLARE @Fields AS TABLE
(
    Field1 VARCHAR(10),
    Field2 VARCHAR(10)
)

--Inserting some values
INSERT INTO @Fields VALUES ('Group 1','Member 1')
INSERT INTO @Fields VALUES ('Group 1','Member 2')
INSERT INTO @Fields VALUES ('Group 1','Member 3')
INSERT INTO @Fields VALUES ('Group 2','Member 1')
INSERT INTO @Fields VALUES ('Group 2','Member 2')
INSERT INTO @Fields VALUES ('Group 3','Member 1')
INSERT INTO @Fields VALUES ('Group 3','Member 2')

--T-Sql
SELECT Field1, Substring(Field2, 2, LEN(Field2)) AS Field2 FROM
(
    SELECT
        [InnerData].Field1,
        (SELECT  ',' + Field2 FROM @Fields WHERE Field1=[InnerData].Field1 FOR XML PATH('')) AS Field2
        FROM
        (
            SELECT DISTINCT Field1 FROM @Fields
        ) AS [InnerData]
) AS OuterData

Display multiple comma separated value into single column output Part II

2008-12-16T03:00:00.001-08:00

Here is the data:

Field1      Field2
----------- --------------------
1           A,B,C
2           A
3           D,G

And we need output as following

Field1               ID
-------------------- ----
1                    A
1                    B
1                    C
2                    A
3                    D
3                    G

Lets create data first.

DECLARE @Fields AS TABLE
(
    Field1 INT,
    Field2 VARCHAR(20)
)

INSERT INTO @Fields VALUES (1,'A,B,C')
INSERT INTO @Fields VALUES (2,'A')
INSERT INTO @Fields VALUES (3,'D,G')

Here is the query for getting expected result.

SET @AnswerXML =
    REPLACE(REPLACE((SELECT
                        Field1, '<Ids><Id value="' + REPLACE(Field2, ',','" /><Id value="') + '" /></Ids>'
                    FROM @Fields
                    FOR XML PATH ('F')
                ), '&lt;', '<'), '&gt;', '>')

SELECT
     Answer.value('Field1[1]', 'BIGINT') as Field1
    ,y.value('@value[1]', 'VARCHAR(1)') AS ID
FROM
    @AnswerXML.nodes('/F') p(Answer)
OUTER APPLY Answer.nodes('Ids/Id') o(y)

Also check Display multiple comma separated value into single column output Part I

Creating comma separated string from Array - LINQ

2008-12-12T02:24:00.001-08:00

Its common requirement to create comma separated string from Array. Using extension methods of LINQ we can do it in single line. Lets create Array first from comma separated values, its simple as we just need to split them using Split function.

string strTest = "1,2,4,6";
string[] Nums = strTest.Split(',');

let's create comma separated string from string Array Nums,

Generally people use foreach loop to create the comma separated string,

But here is the single line code using Lambda Expression to create the same thing.

Console.Write(Nums.Aggregate<string>((first, second) => first + "," + second));
//OUTPUT:
//1,2,4,6

Here the Lambda expression which is accepting two argument and returning the string having concatenation along with delimiter.

Querying Selected Items From ListItemCollection Using LINQ

2008-12-08T01:51:00.001-08:00

Working with ListItemCollection is general practices and getting single value for that it's like child's play. What if you need the list of items which are selected?

I am sure you probably use foreach loop something like

List<ListItem> selectedList = new List<ListItem>();
foreach(ListItem li in cbList.Items)
{
    if (li.Selected)
        selectedList.Add(li);
}

Or advance user use the functionality of C#2.0 using yield keyword

private IEnumerable<ListItem> GetSelectedItems(ListControl listControl)
{
    foreach (ListItem itm in listControl.Items)
    {
        if (itm.Selected)
            yield return itm;
    } 
}
.
.
.
.
.
.
{
    IEnumerable<ListItem> selectedList = new List<ListItem>();
    selectedList = GetSelectedItems(cbList);
}

And now using LINQ C#3.0

var selectedItems =
    from li in cbList.Items.Cast<ListItem>()
    where li.Selected == true
    select li;

The only difference is the Cast, we need to make ListItemCollection generic so we can use it in LINQ query.

And now lets see using Lambda Expression C#3.0

List<ListItem> selectedItems =
    cbList.Items.Cast<ListItem>()
    .Where(item => item.Selected == true).ToList();

Here also we did cast to get the extension method Where. And in Where condition we write the lambda expression instead of anonymous delegate function.

We can even write extension method on base class ListControl so we can have selected items for all the list control. Lets write one extension method on ListControl

public static List<ListItem> SelectedItems(this ListControl lc)
{
    List<ListItem> selectedItems =
                lc.Items.Cast<ListItem>()
                .Where(item => item.Selected == true).ToList();
    return selectedItems;
}

And get the selected items using our extension method we will just call the SelectedItems method.

CheckBoxList cbList = new CheckBoxList();
cbList.SelectedItems();

GROUP BY GROUPING SETS - KATMAI

2008-12-03T23:49:00.001-08:00

IN SQL 2008 KATMAI, there new extension for group by clause. Which is GROUPING SETS. Its provides you to create sets of columns for grouping from you group by column. For example if you have having group on year, month its allow you to group first on year+month then year as single group, which means now you can do multiple grouping in the single query!

Lets see the example. We are having data for Sales. We need sales for each Month as well as each Year. So each year will have again sum of Month. Here is the pictorial representation of last statement.

So our data:

We need this as output:

In SQL 2000/2005 We may need CURSOR or TEMPORARY TABLE or TABLE VARIABLE, and I am sure that will be tedious job. So lets see how we can achieve this functionality in KATMAI using GROUPING SETS. Here is the small and sweet query :)

SELECT 
    S_Year, S_Month, SUM(S_Amt) as AmountSum, AVG(S_Amt) AvgAmt
FROM @Sales
GROUP BY GROUPING SETS ( 
    (S_Year, S_Month)
    ,(S_Year)
    )
ORDER BY S_Year

You can see the new keyword GROUPING SETS which has more then one Group Clause. This indicates that first you do Group on S_Year + S_Month then you Group it on S_Year.

Lets see the output.

You see the NULL in S_Month? That indicates the sum on months for particular Year mean its in the S_Month grouping. And KATMAI provides one function GROUPING which indicates whether a specified column expression in a GROUP BY list is aggregated or not. GROUPING returns 1 for aggregated or 0 for not aggregated in the result set. GROUPING can be used only in the SELECT <select> list, HAVING, and ORDER BY clauses when GROUP BY is specified. Read more on span class="keyword">GROUPING. Lets change query to get proper result.

SELECT 
    CASE 
        WHEN 
            GROUPING(S_Month) = 1 THEN 'Year Total: ' + CAST(S_Year AS VARCHAR(5)) 
        ELSE 
            'Month : ' + CAST(S_Month as VARCHAR(3)) 
        END 
    AS 'Grouping',
    
    SUM(S_Amt) as AmountSum, AVG(S_Amt) AvgAmt
FROM @Sales
GROUP BY GROUPING SETS ( 
    (S_Year, S_Month)
    ,(S_Year)
    )
ORDER BY S_Year, ISNULL(S_Month,15);

And lets see the output.

Download the SQL statements from here.

Check the Origional post

Its very useful while creating Reports.

RadGridNamespace is undefined

2008-12-02T22:00:00.001-08:00

I got error RadGridNamespace is undefined while working with RadGrid and Themes all to gather.

Problem was, It was not able to find the scripts and related files form Themes folder. The default path for Script and Theme for Rad controls are fixed and which is under /RadControls. It goes to that directory but its obvious and convention says that if we are using Themes and Skins we put all the scripts, images and skins in App_Themes folder.

So we need to override the default Rad control default path property RadControlsDir in OnInit method

protected override void OnInit(EventArgs e)
{
    rgTest.RadControlsDir = string.Format("~/App_Themes/{0}/RadControls/", this.Page.Theme);
}

Note: If you are having multiple RadGrid on same page, then you have to set property RadControlsDir for all the grids in OnInit method.

Display multiple comma separated value into single column output

2008-11-28T03:11:00.001-08:00

Here is the data:

Field1      Field2
----------- --------------------
1           A,B,C
2           A
3           D,G

And we need output as following

output
------
A
B
C
A
D
G

Lets create data first.

DECLARE @Fields AS TABLE
(
    Field1 INT,
    Field2 VARCHAR(20)
)

INSERT INTO @Fields VALUES (1,'A,B,C')
INSERT INTO @Fields VALUES (2,'A')
INSERT INTO @Fields VALUES (3,'D,G')

Here is the query for getting expected result.

DECLARE @FieldXml AS XML

DECLARE @v VARCHAR(MAX)

--Creates single row for Field2
SELECT @v = (SELECT ',' + Field2 FROM @Fields FOR XML PATH(''))
--Remove the first comma 
SELECT @v = SUBSTRING(@v, 2, LEN(@v))

--Add the XML tag
SELECT @FieldXml = '<F value="' + REPLACE(@v , ',', '" /><F value="') + '" />'

--List single attribute value
SELECT x.value('@value', 'VARCHAR(1)') AS [output]
FROM @FieldXml.nodes('/F') p(x)

New ASP.NET Charting Control

2008-11-25T20:31:00.001-08:00

Scott Guthrie made announcement about the .NET chart control.

Look at his post. It has links for downloading Controls, VS support download, samples, documents etc.

How to sort Hashtable

2008-11-24T03:49:00.001-08:00

I was having one requirement for sorting Hashtable. In general you cannot choose the sort order of the items added to the Hashtable. To sort Hashtable best practice is to use SortedList. You can either replace Hashtable with SortedList or you convert Hashtable into SortedList and provided your sort expression. Let's see with example. I have one class name ContactActivity which has contact and activity associated with it. I override ToString method to see the the value of added object.

class ContactActivity
{
    public long ActivityId { get; set; }
    public long ContactId { get; set; }

    public override string ToString()
    {
        return string.Format("Contact Id : {0} => Activity Id : {1}", ContactId, ActivityId);
    }
}

Now we will going to create Hashtable and add few objects of type ContactActivity

Hashtable hs = new Hashtable();

hs.Add("3", new ContactActivity() { ContactId = 3, ActivityId = 1 });
hs.Add("4", new ContactActivity() { ContactId = 4, ActivityId = 4 });
hs.Add("6", new ContactActivity() { ContactId = 6, ActivityId = 5 });
hs.Add("1", new ContactActivity() { ContactId = 1, ActivityId = 1 });

One of the constructor of SortedList; except IDictionary and IComparer; Which initializes a new instance of the SortedList class that contains elements copied from the specified dictionary, has the same initial capacity as the number of elements copied, and is sorted according to the specified IComparer interface. We will use that constructor to build SortedList from Hashtable, and also will provide the logic of sorting key by implementing IComparer interface.

Here is the class which implements IComparer interface

public class MySort : IComparer
{
    bool IsAscendingOrder = true;
    #region IComparer Members

    public int Compare(object x, object y)
    {
        if (IsAscendingOrder)
            return (int.Parse(x.ToString()) - int.Parse(y.ToString()));
        else
            return (int.Parse(y.ToString()) - int.Parse(x.ToString()));
    }
    public MySort(bool blnIsAscendingOrder)
    {
        IsAscendingOrder = blnIsAscendingOrder;
    }

    #endregion
}

I added one variable to set the order of key also added constructor which used to set sort order. As in my case key will be integer so I use int.Parse else you can use simply string comparison. Lets create one common method to prints the Hashtable or SortedList, as both implements IDictionary interface we can use that to create common method.

private static void Show(IDictionary id)
{
    foreach (string strKey in id.Keys)
    {
        Console.WriteLine(id[strKey].ToString());
    }
}

So lets put all together.

Hashtable hs = new Hashtable();

hs.Add("3", new ContactActivity() { ContactId = 3, ActivityId = 1 });
hs.Add("4", new ContactActivity() { ContactId = 4, ActivityId = 4 });
hs.Add("6", new ContactActivity() { ContactId = 6, ActivityId = 5 });
hs.Add("1", new ContactActivity() { ContactId = 1, ActivityId = 1 });

Console.WriteLine("Hashtable values");
Show(hs);
Console.WriteLine("Ascending Order");
SortedList sl = new SortedList(hs, new MySort(true));
Show(sl);
Console.WriteLine("Descending Order");
Show(sl);
sl = new SortedList(hs, new MySort(false));

Let's see the output.

Getting value form pervious page into new window

2008-11-20T23:00:00.001-08:00

I saw lots of question posted on http://forums.asp.net/ about how to get the value from pervious page into newly opened window. Its very simple, you have few ways to pass variables to newly opened window. First and foremost is passing variable into query string.

You can get all full form collection; not only this you can also read the value of global variable of parent page in to newly opened window. Let's see how.

I created one variable into parent page. And somewhere I call window.open() to open new page into new window.

<script language="javascript" type="text/javascript">
    var gblPageTitle;
    gblPageTitle = 'Welcome to ';
</script>

In parent page I just have to write following line to get that variable.

<script type="text/javascript">
    document.title = 'Questions on '+ window.opener.gblPageTitle;
</script>

And now lets get the full document of parent page or specifically form collection.

<script type="text/javascript">
    var previousForm = window.opener.document.forms;
</script>

Have fun with window.opener :)

C# ?? operator

2008-11-20T22:21:00.001-08:00

I just found one beautiful operator of C#, which is ?? Its more compact then ternary operator [?:]. Ternary operator is short form of if-else and ?? is also kind of if else, but its work with null value an one assumption. lets see how it works. Its always case when we have to check for null condition, like query string check or Session value check, here how we do to check null for query string.

string strUserId = null;

//Using if-else
if (Request["uid"] == null)
    strUserId = string.Empty;
else
    strUserId = Request["uid"];

//Using ternary operator
strUserId = Request["uid"] == null ? string.Empty : Request["uid"];

now lets use ?? operator

//Using ?? operator
strUserId = Request["uid"] ?? string.Empty;

Isn't it handy? What is does is, it check only for null, it it found left side null then return the value form right hand else it returns left hand site value itself. In our case if there is no uid in query string then will return empty string or else will return the value of uid from query string.

Finding nth maximum number in SQL Server 2005

2008-10-08T00:50:00.001-07:00

This is the frequent requirement for the developer to find the nth max number from the table. It will easy to get it if you are using SQL Server 2005, as its allows us to make the top query variable.

Please read the Flexibility using TOP clause in SQL Server 2005 for more details.

Lets say, we are having student and their marks, and we want the nth max mark. First will see the table structure and will add few data into it.


SET NOCOUNT ON
DECLARE @Marks TABLE
(
    StudName VARCHAR(100),
    Mark INT
)

INSERT INTO @Marks VALUES('AAAAA', 55)
INSERT INTO @Marks VALUES('BBBBB', 65)
INSERT INTO @Marks VALUES('CCCCC', 59)
INSERT INTO @Marks VALUES('DDDDD', 52)
INSERT INTO @Marks VALUES('FFFFF', 65)
INSERT INTO @Marks VALUES('EEEEE', 95)

SELECT Mark FROM @Marks ORDER BY Mark DESC

Mark
-----------
95
65
65
59
55
52

Now we write the query which allow us to find nth max mark form this list.


DECLARE @Top INT
SET @Top = 2

SELECT MIN(Mark) AS 'Top' FROM(
SELECT DISTINCT TOP (@Top) Mark FROM @Marks ORDER BY Mark DESC) A

Top
-----------
65

@Top is variable; which gives you the ability to fetch Nth max.

Matching a delimited string against another delimited string

2008-10-03T06:31:00.001-07:00

I found this is the require thing in our application, as some one in Group asked for help on this as well as one of the member of asp.net forums asked same thing but in different context.

What generally we need is, in our database one field is having multiple value separated with comma. Lets say I am sailor of Property, consider Home as property and features; a bunch of features will create feature group; so home will contains one of the feature group. So here is the feature group table.

SET NOCOUNT ON
DECLARE @FeatureGroup TABLE
(
    PropertyID INT,
    Features VARCHAR(MAX)
)

INSERT INTO @FeatureGroup VALUES(1, 'Gym')
INSERT INTO @FeatureGroup VALUES(2, 'Gym, Swimming Pool')
INSERT INTO @FeatureGroup VALUES(3, 'Swimming Pool, Terrace')
INSERT INTO @FeatureGroup VALUES(4, 'Swimming Pool, Terrace, Gym')
INSERT INTO @FeatureGroup VALUES(5, 'Swimming Pool, Gym, Parking')
INSERT INTO @FeatureGroup VALUES(6, 'Swimming Pool, Terrace, Basement')
INSERT INTO @FeatureGroup VALUES(7, 'Swimming Pool, Gym, Terrace, Basement, Parking')
SELECT * FROM @FeatureGroup 

Gives following output
---------------------------------------------------
1    Gym
2    Gym, Swimming Pool
3    Swimming Pool, Terrace
4    Swimming Pool, Terrace, Gym
5    Swimming Pool, Gym, Parking
6    Swimming Pool, Terrace, Basement
7    Swimming Pool, Gym, Terrace, Basement, Parking

Lets say we have to search for "Gym, Parking", we should list those property which contains either Gym or Parking. There are two way to achieve this, one is using SPLIT function [while is the user define function] and another is XML.

Using SPLIT Function:

Its user define function which splits the comma separated value to Table variable. In this case we first split our filter using Split function which will return the rows representation of our filter; mean each filter will be in separate row. Lets see the definition of Split function.

CREATE function [dbo].[Split](@String nvarchar(4000), @Delimiter char(1))
RETURNS @Results Table (Item1 nvarchar(100))
As    
Begin    
    DECLARE @Index int    
    DECLARE @Slice nvarchar(100)    
     
    SET @Index = 1    
    
    IF @String Is NULL Return    
    
    WHILE @Index != 0    
    BEGIN    
        SELECT @Index = CharIndex(@Delimiter, @String)    
        If @Index != 0    
            SELECT @Slice = LEFT(@String, @Index - 1)    
        else    
            SELECT @Slice = @String    
    
        INSERT INTO @Results VALUES(RTRIM(LTRIM(@Slice)))
      
        SELECT @String = RIGHT(@String, LEN(@String) - @Index)
        IF LEN(@String) = 0 BREAK    
     END    
    RETURN    
END

Here is the use of Split.

SELECT * FROM [master].[dbo].[Split] ('Gym, Parking', ',')

Item1
--------
Gym
Parking

Now lets write query which uses Split function.

DECLARE @Filter VARCHAR(100)
set @Filter = 'Gym, Parking'

select PropertyId, Features from @FeatureGroup FG WHERE -1 IN (
     SELECT CASE WHEN (PATINDEX('%' + Item1 + '%', FG.Features)) > 0 THEN -1 ELSE 0 END
     FROM [master].[dbo].[Split] (@Filter, ','))

Here is the output:
-------------------------------------------------------
1    Gym
2    Gym, Swimming Pool
4    Swimming Pool, Terrace, Gym
5    Swimming Pool, Gym, Parking
7    Swimming Pool, Gym, Terrace, Basement, Parking

And now lets do it with XML.

DECLARE @Filter VARCHAR(100)
set @Filter = 'Gym, Parking'

DECLARE @xmlFilter XML
SELECT @xmlFilter = CAST('<i>' + REPLACE(@Filter, ',', '</i><i>') + '</i>' AS XML)

SELECT DISTINCT    
    PropertyID, Features
FROM @FeatureGroup FG
CROSS JOIN (
    SELECT 
        x.i.value('.', 'VARCHAR(10)') AS filter
    FROM @XmlFilter.nodes('//i') x(i)
) b
WHERE PATINDEX('%' + b.filter + '%', features) > 0

OUTPUT:
-------------------------------------------------------
1    Gym
2    Gym, Swimming Pool
5    Swimming Pool, Gym, Parking
7    Swimming Pool, Gym, Terrace, Basement, Parking
4    Swimming Pool, Terrace, Gym

You can find the details of how XML works in here, you can read the TSQL Labs 13 - Matching a delimited string against another delimited string created by Jacob Sebastian

Changing the value of web.config file runtime

2008-10-03T01:06:00.001-07:00

There is pretty small and simple code to change the value of key defined in web.config file.

// Get the reference of the configuration file at the root.
Configuration objConfig = System.Web.Configuration.WebConfigurationManager.OpenWebConfiguration("~");
// Change the value of one key
Response.Write(string.Format("Old value : {0}<br/>", objConfig.AppSettings.Settings["MyKey"].Value));
objConfig.AppSettings.Settings["MyKey"].Value = "changed web config";
// Save the changes.
objConfig.Save();
Response.Write(string.Format("New value : {0}", objConfig.AppSettings.Settings["MyKey"].Value));

Transfer rows to column in C#

2008-10-03T00:36:00.000-07:00

I was having requirement to change result of SQL in such a way that rows become columns, and columns become rows.

PersonName                Year2000               Year2001               Year2002               Year2003
------------------------- ---------------------- ---------------------- -------------------    ---------------
A                         1230                   4521                   5435                   5410
B                         1330                   4231                   5435                   1200
C                         3230                   1623                   5435                   3652
D                         4230                   2321                   5435                   1859

And need output as following

SalesYear       A                      B                      C                      D
--------------- ---------------------- ---------------------- ---------------------- ----------------------
Year2000        1230                   1330                   3230                   4230
Year2001        4521                   4231                   1623                   2321
Year2001        5435                   5435                   5435                   5435
Year2001        5410                   1200                   3652                   1859

Mr Jacob wrote post on this which is uses UNPIVOT operator which is in SQL Server 2005, you can find it here.

Here is the contributed code form Abidali Suthar [one of the developer in my team], which does the same thing but in C#.

I added extension method to DataTable, by calling SwapTable method on any DataTable instance; you can get the rows in columns and columns in rows. Lets look at extension method first.

public static class DatatTableExtension
{
    /// <summary>
    /// Extension method which transform row to column and column to row
    /// </summary>
    /// <param name="dt">Object on which we have to do operation</param>
    /// <returns>Transformed DataTable object</returns>
    public static DataTable SwapTable(this DataTable dt)
    {
        if (!(dt.Columns.Count > 0 && dt.Rows.Count > 0))
            return dt;

        DataTable dtNew = new DataTable();
        dtNew.Columns.Add(dt.Columns[0].ColumnName);

        // Creating columns for new DataTable. 
        // Adding column to new data table having name as first row of old data table
        for (int i = 0; i <= dt.Rows.Count - 1; i++)
            dtNew.Columns.Add(dt.Rows[i][0].ToString());

        DataRow row;
        // Swaping the values
        for (int k = 1; k < dt.Columns.Count; k++)
        {
            row = dtNew.NewRow();
            row[0] = dt.Columns[k].ToString();
            for (int j = 1; j <= dt.Rows.Count; j++)
                row[j] = dt.Rows[j - 1][k];

            dtNew.Rows.Add(row);
        }

        return dtNew;
    }
}

As we created extension method, its now easy to call it by creating object of DataTable. Lets see with example.

protected void Page_Load(object sender, EventArgs e)
{
    using (SqlConnection con = new SqlConnection("CONNECTION_STRING"))
    {
        con.Open();
        string strSelect = "SELECT_STATEMENT";

        SqlCommand cmd = new SqlCommand(strSelect, con);
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataTable dt = new DataTable();
        da.Fill(dt);
        con.Close();

        // Bind original datatable
        dgBefore.DataSource = dt;
        dgBefore.DataBind();

        // Bind swapped datatable, calling extension method on datatable5
        dgAfter.DataSource = dt.SwapTable();
        dgAfter.DataBind();
    }
}

Error: Validation of viewstate MAC failed

2008-09-30T05:14:00.001-07:00

This is common error generally working with UpdatePanel.

On your screen you see message "Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster."

You can fix it in two ways, setting in web.config or in page it self.

In web.config:

<pages enableEventValidation="false" viewStateEncryptionMode ="Never" />

Or in page you write following line in @Page directive.

<%@ Page EnableEventValidation="false" ViewStateEncryptionMode="never" ...

Silverlight 2 Release Candidate Now Available

2008-09-25T23:02:00.001-07:00

Hello All,

Silverlight 2 is now available, please read this post of Scott Guthre

with operator in JavaScript

2008-09-24T20:39:00.001-07:00

Hello Friends,

I found one good thing in JavaScript, there is with operator in JavaScript, which you can say same as with operator in VB.NET. Its always helpful to define short name of big variable or replacement of such big variable; which lead us to make code more readable and maintain too.

In general when we are dealing with XML datasrouce in JavaScript; there always have long long variable name, of the value is so deep inside.

xmlDoc.childNodes[1].childNodes[0].childNodes[3].childNodes[0].text
xmlDoc.childNodes[1].childNodes[0].childNodes[4].childNodes[0].text

We have to write more lines of code to get all the details. Here we can use with, as we know part of path to reach final value is common which is xmlDoc.childNodes[1].childNodes[0], so we can put it into with keyword.

with(xmlDoc.childNodes[i].childNodes[0])
{
    name = childNodes[1].childNodes[0].text;
    add1 = childNodes[2].childNodes[0].text;
    add2 = childNodes[3].childNodes[0].text;
    email = childNodes[4].childNodes[0].text;
    .
    .
    .
}

How to get Property list only of Derived class?

2008-09-22T23:41:00.001-07:00

Hi All,

Recently I seen one requirement on ASP.Net Forum, some one posted question about How to get property list of Derived class.

Generally if we want to get all the property of class we use GetProperties() method. Which gives you the PropertyInfo[]. Lets see with example. We have following class Hierarchy.

class A
{
    public int Id { get; set; }

    public virtual void PrintMe()
    {
        Console.WriteLine("Id : " + Id);
    }

}

class B : A
{
    public string Name { get; set; }
    public string Address { get; set; }
    public override void PrintMe()
    {
        base.PrintMe();
        Console.WriteLine("Name : " + Name);
    }
}

In A there is only one property and in B we have 2 more property, our goal to get only two property declared in class B. Lets check with GetProperties().

PropertyInfo[] properties = typeof(B).GetProperties();

Console.WriteLine(properties.Count()); //will print 3

You can see its printing 3, that means it consider properties which are in parent and child too. There is one overload of GetProperties() which has BindingFlags, but with that also we are not achieving our goal.

So here is the solution using LINQ.

var prop =
    from
        p in typeof(B).GetProperties()
    where p.DeclaringType == typeof(B)
    select p;

Console.WriteLine(prop.Count()); //Will print 2

We are filtering on DeclaringType; which should be typeof(B). You can see now its returning 2, that what we needed.

Windows live writer for server 2003

2008-09-21T22:38:00.001-07:00

Hello All,

This post is related to people who are creating blog using Window Live Writer.

It took me long to get the Windows Live Writer for Server 2003. Here is the link to download the Windows Live Writer for Server 2003

User Group Meeting on 20-Sep-2008

2008-09-18T20:59:00.000-07:00

Hi All,

This is to announce that there is next meeting of Ahmedabad_SQLServer_UserGroup on Saturday, September 20, 2008.

I would like you to join this and meeting inperson and gain lots of knowledge shared by MVPs, there always a QA session at the end of each meeting followed by ICE-CREAM.

The topic of this meeting will be CTE and Pinal Dave [MVP] will be the speaker of this meeting.

To Register: Click Here.
To View Meeting Details : Click Here.
Not member of this group?: Click here

In previous meeting we explore the SQL Server Transaction Isolation Levels, which was presented by Jacob Sebastian [MVP, MSDN moderator, Owner of groups, and lots more], that was wonderful session along with live demos. If you miss that event then you can go here

Visual Studio IDE Support for SQL Server

2008-09-18T00:29:00.000-07:00

Hello,

As we all know Visual Studio is now supporting Database project, which allows you to write query, procedure etc... from IDE only.

Recently I found the error while connecting SQL2008 from VS2008.

This server version is not supported. Only servers up to Microsoft SQL Server 2005 are supported.

I found after doing some googling; that there is no patch available which allos me to connect SQL2008 to VS2008!!!.

I found few comments which says that it will come soon.

Somasegar's WebLog
Euan Garden's BLOG

However there is Sservice Pack for Visual Studio 2008 Team Foundation Server which has ability to Support for SQL Server 2008, you can download that form Microsoft Download Center

Let me add that there is Service Pack for Visual Studio 2005 Support for SQL Server 2008, which you can download it from Microsoft Download Center

Reducing page load times with UpdatePanels and timers

2008-09-16T22:51:00.000-07:00

Hi all,

Some time we have requirement like, on single page we are having 5-6 controls, which at the same tiem only single is visible and by navigation we can view all other controls.

This is very specific to Ajax Tab Implementation. Where we are having 4-5 tabs, in which we are having server controls, so on Page load all the controls get loaded and page become heavy also slow.

There is one technique to optimize this. As we all know we have to show single tab once page is get loaded, put all the controls into Asp:Panel and except one which we have to show on default; make other to visible false. The enable of all visible panel will be done using timer control. Time control will make enable the Asp:Panel one by one. As all the Asp:Panel will be in UpdatePanel will page will not get refreshed.

I found the same code in one of the post of Glavs Blog.

He provides the code along with video. Have a look at them and make optimize your page. I used this and found very good, even we can now use this on same page.

Why doesn't C# support multiple inheritance?

2008-09-14T10:19:00.000-07:00

Hi all,

I was always searching for the answer of "Why doesn't C# support multiple inheritance?".

After some googling I found the answer from MSDN.

Please have a look at the link.

Finding occurrences of character in string [LINQ]

2008-09-10T21:54:00.000-07:00

Hello All,

This is normal requirement when you need to find the occurrence of single character with in the string. Here is the example which uses LINQ to achive this.

string strString = "AA BRA KA DABRA";

var grp = from c in strString.ToCharArray() 
        group c by c into m
        select new { Key = m.Key, Count = m.Count() };

foreach (var item in grp)
{
    Console.WriteLine(
        string.Format("Character:{0} Appears {1} times", 
        item.Key.ToString(), item.Count));
}

Extended URL rewriting

2008-09-09T00:33:00.000-07:00

I was having one requirement for my .net application. In which I want to parse the following url. Handling request with out extension.

http://mysite.com/imran/
http://mysite.com/armaan/

For these url we can't user ASP.NET URL Re-Writing, as there is no aspx extension added to this url.

When you found such request and its not exists then IIS will give 404 error, but we need to parse such url and do some validation and give them proper output. In this case lets say I would like to see the profile of user imran, then I make request to http://mysite.com/imran/ which gives me the profile of user imran.

This is the normal requirement, we can do it easily in php and java. But in .net this is bit tricky to get such functionality working.

If we use http handler, then also we are not able to identify the request as it has no extension. As its is not reaching to the application, IIS itself reject this request, no global.ascx or web.config

I found very easy solution for this solution. This requires some setting on virtual directory and code in our system to handle such request.

As I mention eariler when you send request to http://mysite.com/imran/ which not exist; IIS will raise 404 error, what we do is, we trap this error and get the requested page or url and do some work and give the result.

IIS Setting
In IIS we have to change default 404 error handling to aspx page, bye default 404 page is C:\WINDOWS\help\iisHelp\common\404b.htm with Message Type as File. See the image

We need to change this to forward all such request to our application, once we got control in aspx page then we can do anything on such request.

For this we need to change Message Type, set it to URL and the URL will be /MySite/Handle404.aspx. See the image

Code
We have to write few lines of code in Handle404.aspx to handel this request.

protected override void OnInit(EventArgs e)
{

    if (Request.Url.ToString().Contains("404;"))
    {
        string[] urlInfo404 = Request.Url.Query.ToString().Split(';');

        if (urlInfo404.Length > 1)
        {
            string strRequestUrl = urlInfo404[1].Replace(":" + Request.Url.Port + "/", "/");

            if (!strRequestUrl.EndsWith("/"))
            {
                strRequestUrl = strRequestUrl.Insert(strRequestUrl.Length, "/");
                Response.Redirect(strRequestUrl);
            }
            string[] urlInfoFavAddress = strRequestUrl.Split('/');
            string strUser = urlInfoFavAddress[urlInfoFavAddress.Length - 2];

            Server.Transfer(string.Concat("~/Profile.aspx?usr=", strUser));

        }
    }
    base.OnInit(e);
}

Here we are just grabbing the trailing string, in this case its imran or armaan.

Once I get the key its get redirected to Profile page, as its Server.Transfer which does not change the url.

Load method of DataTable

2008-09-05T23:05:00.000-07:00

I found very interesting method of DataTable. There is Load method which loads the IDataReader directly to DataTable. Well this is not interestring I know lolz.

The case is like....

My query or procedure generates 4 different result set, and I have 4 different DataTable. As IDataReader has 4 result set, fatching all result set I have to use NextResult method which put my reader to next result set. like this. [Dont know this??? Have a look at this.]

DataTable dt1 = new DataTable();
DataTable dt2 = new DataTable();
DataTable dt3 = new DataTable();
DataTable dt4 = new DataTable();
DataTable dt5 = new DataTable();

using (SqlConnection con = new SqlConnection("CONNECTION_STRING"))
{
    SqlCommand cmd = con.CreateCommand();
    cmd.CommandType = CommandType.Text;
    cmd.CommandText = "select * from TABLE1;select * from TABLE1;select * from TABLE2;select * from TABLE3";

    con.Open();
    IDataReader idr = cmd.ExecuteReader();

    dt1.Load(idr);
    idr.NextResult(); // Put DataReader to next result set
    dt2.Load(idr);
    idr.NextResult(); // Put DataReader to next result set
    dt3.Load(idr);
    idr.NextResult(); // Put DataReader to next result set. ERROR
    dt4.Load(idr);                
}

But this get fails at NextResult, why?

Because when you call Load method on DataTable, it automatical set pointer to next result set, we dont need to call NextResult here.

This is interesting thing, lets add few more on it. First we remove the NextResult method.

DataTable dt1 = new DataTable();
DataTable dt2 = new DataTable();
DataTable dt3 = new DataTable();
DataTable dt4 = new DataTable();
DataTable dt5 = new DataTable();

using (SqlConnection con = new SqlConnection("CONNECTION_STRING"))
{
    SqlCommand cmd = con.CreateCommand();
    cmd.CommandType = CommandType.Text;
    cmd.CommandText = "select * from TABLE1;select * from TABLE2;select * from TABLE3;select * from TABLE4";

    con.Open();
    IDataReader idr = cmd.ExecuteReader();

    dt1.Load(idr);
    dt2.Load(idr);
    dt3.Load(idr);
    dt4.Load(idr);
    dt5.Load(idr);
}

Well this is working fine, can you see the dt5? I am trying to load 5th result set, but there is no such result set produced by my Sql statements, its still working!!!!, this is really interesting. Well its not succesfull operation; but its will make empty DataTable.

Make temporary redirection to another page

2008-09-03T21:43:00.000-07:00

Hello All,

I got one question is asp.net forums, some time people require to change the location automatically or the best example is like, when you shifted your site to new location and you dont want people [who bookmarked your site] request to old site locaiton and get page not found error!

This case what you can do is, you can add automatic redirection to the new site, just adding the meta tag.

You can create one html file or you can write meta tag in older site's default page, here is the meta tag, you just have to place in head tag

<meta http-equiv="refresh" content="5;url='http://knowledgebaseworld.blogspot.com/'" />

http-equiv is the command, which says refresh, so it have to do refresh, and in the content we have to set new locatoin and the time in second. Here its 5 so after 5 second it will automatically redirected to http://knowledgebaseworld.blogspot.com.

We can put some thing like, the page you are looking for its moved, please wait, we are redirecting to new page, book mark this page bla bla bla.....

This way we stop loosing our valuable users of site.

Creating Rad Menu using LINQ

2008-09-03T01:13:00.000-07:00

Hello all,

I created sample code to generate Dynamic RadMenu with use of LINQ. The controls like RadMenu, AspMenu which accept XML as the datasource to generate the output.

I use LINQ to generate XML, you can read here to generate XML using LINQ.

You can find the simple project at Code Project. You can modify the code with your use, its dynamically creates the node also it uses the recursion to generate n level menu item.

Best way to generate XML using LINQ

2008-08-19T20:13:00.000-07:00

Hi all,

As we know C# 3.0 with LINQ gives us lots of power and smart coding, here is one more example which uses features of LINQ to generating XML of the abstract type.

I will give you example where you need to display the person details along with the address, here address can be anything like home address, email address, IM address ...

Here are the classes which require to achive our goal.

class Person
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public List<Address> Address = new List<Address>();
}
 
class Address
{
    public string AddressValue { get; set; }
    public string Type { get; set; }
}

Person class used to store person data, and Address class which holds the type of address.
Now lets add few details.

Person Person1 = new Person() { FirstName = "Imran", LastName = "Bhadelia" };
Person1.Address.Add(new Address() { Value = "imran.bhadelia[at]gmail.com", Type = "Email" });
Person1.Address.Add(new Address() { Value = "bhadelia.imran[at]gmail.com", Type = "AlternativeEmail" });
Person1.Address.Add(new Address() { Value = "bhadelia.imran[at]gmail.com", Type = "MSNInstanceMessanger" });
Person1.Address.Add(new Address() { Value = "bhadelia.imran", Type = "YahooInstanceMessanger" });
 
Person Person2 = new Person() { FirstName = "Armaan", LastName = "Bhadelia" };
Person2.Address.Add(new Address() { Value = "armaan.bhadelia[at]gmail.com", Type = "Email" });
Person2.Address.Add(new Address() { Value = "Sweet Home, 406 Paradise Palace...", Type = "Residence" });
Person2.Address.Add(new Address() { Value = "bhadelia.armaan[at]gmail.com", Type = "MSNInstanceMessanger" });
Person2.Address.Add(new Address() { Value = "bhadelia.armaan", Type = "YahooInstanceMessanger" });
 
List<Person> PersonList = new List<Person>();
PersonList.Add(Person1);
PersonList.Add(Person2);

Here I used one feature of C#3.0, which is Object Initialization Expressions. See the constructor of both class, Its default and while creating object I am setting the value to the fields of class [Smart coding]. I added this two class into List variable, from where LINQ will generate XML which looks like...

<Persons>
    <Person FirstName="Imran" LastName="Bhadelia">
        <Address Email="imran.bhadelia[at]gmail.com" /> 
        <Address AlternativeEmail="bhadelia.imran[at]gmail.com" /> 
        <Address MSNInstanceMessanger="bhadelia.imran[at]gmail.com" /> 
        <Address YahooInstanceMessanger="bhadelia.imran" /> 
    </Person>
    <Person FirstName="Armaan" LastName="Bhadelia">
        <Address Email="armaan.bhadelia[at]gmail.com" /> 
        <Address Residence="Sweet Home, 406 Paradise Palace..." /> 
        <Address MSNInstanceMessanger="bhadelia.armaan[at]gmail.com" /> 
        <Address YahooInstanceMessanger="bhadelia.armaan" /> 
    </Person>
</Persons>

And now LINQ to generate above XML.

var PersonXml =
    new XElement("Persons",
        from person in PersonList
        select (new XElement("Person",
            new XAttribute("FirstName", person.FirstName),
            new XAttribute("LastName", person.LastName),
 
            from addr in person.Address
            select new XElement("Address", new XAttribute(addr.Type, addr.Value)))));

Console.WriteLine(PersonXml.ToString());

How it works??
Line#2: Create the main element which is Persons
Line#3: Getting single Persons object from PersonList
Line#4: Creating sub element to Persons which is Person
Line#5&6: Creating attributes to show person details.
Line#8: Getting Address of the person from Address collection
Line#9: Creating Address element along with the attribute

Easy? I found its very easy :)

Now if you want to add this information into SQL Server 2005 and higher, you can pass it as string and in your procedure grab the value. There are lots of way to grab value from XML in SQL, you can check this url, it has almost all the operations to XML datatype in SQL.

I created SQL script for specific to this xml.

SELECT 
    Person.value('@FirstName[1]', 'VARCHAR(100)') as FirstName,
    Person.value('@LastName[1]', 'VARCHAR(100)') as LastName,
    Person.value('(Address/@Email)[1]', 'VARCHAR(100)') as Email,
    Person.value('(Address/@AlternativeEmail)[1]', 'VARCHAR(100)') as AlternativeEmail,
    Person.value('(Address/@Residence)[1]', 'VARCHAR(100)') as Residence,
    Person.value('(Address/@MSNInstanceMessanger)[1]', 'VARCHAR(100)') as MSNInstanceMessanger,
    Person.value('(Address/@YahooInstanceMessanger)[1]', 'VARCHAR(100)') as YahooInstanceMessanger
FROM @Persons.nodes('/Persons/Person') p(Person)

Getting child ids in string separate with delimiter along with parent id[SQL SERVER]

2008-08-13T23:32:00.000-07:00

Hi Friends,

I come accros one requirement where I need... the child id should be delemited by '|' and along with the parent Id. Lets say I am having parent as company, one company is having more then one code.

So now my requirement is to get the company code in '|' saperated with company id, just like this.

Comp_id     company_code
----------- ------------
1           1|2
2           1|2|3|4
3           1|2

We can achive this by either using a user-defined aggregate function or using loop. I will explore the user-defined aggreagate function and post how to do, but for now lets do it with looping. Here is the code to achive this by using while-loop.

DECLARE @companies Table
(
    Comp_id INT,
    company_code  int
)
 
insert into @companies values(1,1)
insert into @companies values(1,2)
insert into @companies values(2,1)
insert into @companies values(2,2)
insert into @companies values(2,3)
insert into @companies values(2,4)
insert into @companies values(3,1)
insert into @companies values(3,2)
 
DECLARE @TmpTable Table
(
    Id int IDENTITY (0, 1) NOT NULL,
    CompanyId INT
)
 
SET NOCOUNT ON
 
DECLARE @Tmpcompanies Table
(
    Comp_id int,
    company_code  varchar(10)
)

INSERT INTO @TmpTable SELECT DISTINCT comp_id FROM @companies
 
DECLARE @MaxId INT
DECLARE @PipedList VARCHAR (MAX)
Declare @Count INT
Declare @CurrComp INT
 
SELECT @MaxId = MAX(id) FROM @TmpTable
SET @Count = 0
WHILE( @Count <= @MaxId)
BEGIN
    SET @PipedList = NULL
    SELECT @CurrComp = Comp_id, @PipedList = COALESCE(CAST(@PipedList AS VARCHAR(MAX)) + '|', '') 
    + CAST(company_code AS VARCHAR(10)) FROM @companies Cmp, @TmpTable TT
        WHERE CMP.Comp_id = TT.CompanyId AND TT.ID = @Count
    INSERT INTO @Tmpcompanies VALUES(@CurrComp, @PipedList)
    SET @Count = @Count + 1
END
 
SELECT * FROM @Tmpcompanies

How to sort generic collection

2008-08-12T01:36:00.000-07:00

Hi all,

We will now sort generic collection. For this we need to create one comparere class which inherits IComparer<T> and implement Compare method, where T is your class object. Compare method is responsible to compare tow object and based on the result sorting will be done.

public class TestSortComparere : IComparer<TestSort>
{
    public TestSortComparere() { }

    #region IComparer<TestSort> Members

    public int Compare(TestSort x, TestSort y)
    {
        return string.Compare(x.a, y.a);
    }

    #endregion
}

Now lets call Sort method.

List<TestSort> MyObjList = new List<TestSort>();
MyObjList.Add(new TestSort("Imran"));
MyObjList.Add(new TestSort("Dipak"));
MyObjList.Add(new TestSort("Sachin"));
MyObjList.Add(new TestSort("Darshan"));
MyObjList.Add(new TestSort("Gaurav"));

MyObjList.Sort(new TestSortComparere());

You can see the sorted order when you iterate MyObjList

foreach (TestSort testSort in MyObjList)
    Console.Write(testSort.strTest + Environment.NewLine);
//OUTPUT
/*
 Darshan
 Dipak
 Gaurav
 Imran
 Sachin
 */

We can change the sort line using Anonymous delegate. Lets see how, its only in single line!!!!.

MyObjList.Sort(delegate(TestSort x, TestSort y) { return string.Compare(x.strTest, y.strTest); });

Difference between internal and protected internal

2008-08-12T01:01:00.000-07:00

Hi All,

Generally what we assume that internal means the variable that can only accessed within the assembly [which is the collection of namespace and classes].

But there is slide different meaning when we add protected to an internal member. What is that? The difference is... if you created a member which is protected internal then you can get it outside the assembly, but condition that you derive that class. Its protected so if you derive that class then in child class you can access the protected internal member.

We can check it out with example. Lets have a look at the classes which are in same assembly.

namespace Understand
{
    public class C : UnderstandInternal.Class1
    {
        public C()
        {
            base.intInternalProtected(); // can call anything
            base.intInternal();
        }
    }
}


namespace UnderstandInternal
{
    public class Class1
    {
        internal int intInternal() { return 1; }
        internal protected int intInternalProtected() { return 3; }
    }


    public class Class3
    {
        Class1 c = new Class1();
        public Class3()
        {
            c.intInternalProtected(); // can call anything
            c.intInternal();
        }
    }
}

You can see there is no problem in accessing the variable, its working fine, now we will do same thing in different assembly. Lets look at the following classes.

namespace TestConsole
{
    class InternalTest : Class1
    {
        public InternalTest()
        {
            base.intInternalProtected(); //your can use here
            base.intInternal(); //Error: 'UnderstandInternal.Class1' does not contain a definition for 'intInternal'

        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            Class1 c = new Class1();
            c.intInternalProtected(); //Error: 'UnderstandInternal.Class1.intInternalProtected()' is inaccessible due to its protection level
            c.intInternal(); //Error: 'UnderstandInternal.Class1' does not contain a definition for 'intInternal' and no extension method 'intInternal'
        }
    }
}

Transferring control from ascx to aspx

2008-08-12T00:56:00.000-07:00

Hi all,

In many cases we require some functionality in which there is something happening at control level and we need to notify to page level. Mainly when we are creating control which has grid or some short of dataview control and there is need to pass some message to page [in which the control is loaded] from any event.

This article will help you to achive this using a powerful functionality provided by .NET framwork which is delegate. Delegate in C# is similar to a function pointer in C or C++. Using a delegate allows the programmer to encapsulate a reference to a method inside a delegate object. The delegate object can then be passed to code which can call the referenced method, without having to know at compile time which method will be invoked.

Our goal is to display the messages on page [aspx] about which row is currently selected. We will create one event in control [ascx] which will be handeled in page [aspx], for creating event we need to create one delegate first.

public delegate void SelectedIndexChanging(object sender, GridViewSelectEventArgs e);

SelectedIndexChanging is the delegate which has same argument as GridView's SelectedIndexChanging event.

Now will create Event of the type SelectedIndexChanging delegate in ascx

public event SelectedIndexChanging GridViewSelectedIndexChanging;

How to call this event? Well we have to call this event on the same event of Grid in ascx, so we can raise this event and in page [aspx] we can capture this and do the some operation.

protected void gvTest_SelectedIndexChanging(object sender, GridViewSelectEventArgs e)
{
    if (GridViewSelectedIndexChanging != null)
        GridViewSelectedIndexChanging(sender, e);
}

Why null condition check? We have to check whethere there is any handler to this event or not, if there is no handler bound then no need to raise this event, else it will thro Exception :)
We are ready with our user control, now place this on page and bind the hendler to SelectedIndexChanging event, here is the bind code.

childControl.GridViewSelectedIndexChanging += new ChildControl.SelectedIndexChanging(childControl_GridViewSelectedIndexChanging);

And in method I am just displaying the selected item details.

void childControl_GridViewSelectedIndexChanging(object sender, GridViewSelectEventArgs e)
{
    GridViewRow gvr = (sender as GridView).Rows[e.NewSelectedIndex];
    lblGridSelectedFor.Text = string.Format("Id = {0}, Name = {0}",
    (gvr.FindControl("lblIdentity") as Label).Text, (gvr.FindControl("lblName") as Label).Text);
}

As I passed the same sender along with GridViewSelectEventArgs, I can access all the events and gridview here. First I cast sender in GridView to get the GridView which is inside user control, and from NewSelectedIndex, I read some value and displaying using label.

And this way we achive our goal, you can do lots many thing by use of Delegates, you can also read the article on Anonymous Delegate and Delegates and Events in C# / .NET

Parent can hold reference of Child

2008-08-09T04:11:00.000-07:00

Hello all,

We all know that A a = new B(); we learn this by heart from the day we start OOPS.

But there are lots many people who just do cramming lolz, I have one good example which helps you to get your mind set what is meaning of A a = new B();

We all know that using virtual function we can achive the golden word "Parent can hold reference of child", but its not just virtual function involved, there are also reusability.

Lets say you have one base class having 10 properties and you derived 2 more classes which individual has more then 5-5 properties.

So what I do? Should I create methods for each child class? What if I have more 2-3 class?? The answer is NO [I knew that you know it :)]

So what to do? How A a = new B(); will help full here?

Lets learn with example.

I am haivng A as parent class and B, C as child class.

class A
{
    public int Id { get; set; }

    public virtual void PrintMe()
    {
        Console.WriteLine("Id : " + Id);
    }

}

class B : A
{
    public string Name { get; set; }

    public override void PrintMe()
    {
        base.PrintMe();
        Console.WriteLine("Name : " + Name);
    }
}

class C : A
{
    public string Company { get; set; }
    public override void PrintMe()
    {
        base.PrintMe();
        Console.WriteLine("Company : " + Company);
    }
}

You can see the virtual method; this is the key thing to see the power of A a = new B();.

Now the method call, here is the code to calling method PrintMe


A a = new B();
a.PrintMe();    //will call B method            
a = new A();
a.PrintMe();    //Will call A method
a = new C();
a.PrintMe();    //Will call C method

There is nothing wrong in it, it can easily understood.

Now our purpose, what is it? Yes we need to set properties and then call PrintMe method.


private static void CallMe(A a)
{
    a.Id = 4;

    if (a is C)
        ((C)a).Company = "My Company";
    else if (a is B)
        ((B)a).Name = "My Name";
    a.PrintMe();
}

See the signature of this method, it says private static void CallMe(A a), the parameter is object of class A; that is PARENT. And inside it the first line is setting the property of parent and then based on the type the rest of properties is getting populated. And at the end calling PrintMe which is virtual so based on reference it will call the method.

Lets call method CallMe.


1. a = new B();
2. CallMe(a); //Will print Id and Name
3. a = new C();
4. CallMe(a); //Will print Id and Company

1st line creating object of B and setting it to A'a object. 2nd linke calling CallMe by passing the parent object. This will first set the property of child and then as its B's object will set the property of Name and call PrintMe, which give call to B's PrintMe method [remember virtual].

So, this is the real world use of A a = new B();

Hope you understand, any question any query please feel free to approch me.

Inserting collection of string to DB with duplicate check

2008-08-08T23:26:00.000-07:00

Hi all,

We need some kind of functionality where from frontend [ASP.NET] we pass the comma or semicolon saperated strings into database for inserting purpose and also we need to check the duplication of the string.

With the world of XML we can do this easily, here is the Sql Script to do so. My string collection is the email list, i have to insert multiple emails and also need to check for the duplication. at the end I get the duplicate email list, which can be easily get form Frondend [ADO.NET] using output param or any other way.

SET NOCOUNT ON

DECLARE @Table AS TABLE
(
    Email VARCHAR(100)
)
 
INSERT INTO @Table VALUES('a@b.com')
INSERT INTO @Table VALUES('c@d.com')
  
DECLARE @EmailList VARCHAR(MAX)
DECLARE @XMLEmailList XML
  
SELECT @EmailList = 'a@b.com;c@d.com;aa@aa.com;fads@ddd.com'
SELECT @XMLEmailList= '<email>' +  REPLACE(@EmailList, ';', '</email><email>') + '</email>'
  
DECLARE @DuplicateEmail VARCHAR(100)
  
SELECT @DuplicateEmail = COALESCE(CAST(@DuplicateEmail AS VARCHAR(MAX)) + ';', '') + + CAST(a.value('.', 'varchar(100)') AS VARCHAR(10))
FROM @XMLEmailList.nodes('/email') v(a)
WHERE a.value('.', 'varchar(100)') in (SELECT Email FROM @Table)
  
INSERT INTO @table
SELECT a.value('.', 'varchar(100)')
FROM @XMLEmailList.nodes('/email') v(a)
WHERE a.value('.', 'varchar(100)') not in (SELECT Email FROM @Table)
  
SELECT @DuplicateEmail
SELECT * FROM @Table

Inserting value of Collection into Database

2008-08-08T05:15:00.000-07:00

We always require thing like this, when you need to Insert list of object at the same time with single database operation.

Generally what we are doing is inserting individual object from front end, which is not good idea; in case where you have 100 of object needs to be inserted same time.

With the new feature Extension Method included in C# 3.0 and the XML datatype provided in SQL Server 2005, with combining these two we can achive the goal with less affort in terms of traffic and compactness of code.

I posted code on Code Project, it has description of each important phase you can download and customize according your need.

Remove duplicate comma from list

2008-08-07T21:47:00.000-07:00

Hi,

Recently on ASP.NET forum there was post for removing duplicate ',' from a comma saperated string.

This is using Regex

string abodes = ",House,,,,Apartment,,,Villa,,,,Townhouse,,,,";
Regex regx = new Regex(@",+");
abodes = regx.Replace(abodes, ",").Trim(',');

And now let's see using LINQ

string abodes = ",House,,,,Apartment,,,Villa,,,,Townhouse,,,,"; 
string cleanAbodes = string.Join(",", abodes.Split(',').Where(a => a != string.Empty).ToArray());

Have Fun with LINQ

Expression in ASP.NET

2008-08-04T06:38:00.000-07:00

What if I want to show the value of the key defined in Web.config file on a ASPX page? Or for testing purpose if we want to show the value of connection string??

Here is the Web.Config file entries...

<appSettings>
    <add key="ImageFolder" value="C:\Temp"/>
</appSettings>
<connectionStrings>
    <add name="DBConnection" providerName="System.Data.SqlClient"
         connectionString="Data Source=[DataSource];Initial Catalog=[InitialCatalog];
         User ID=[UserID];Password=[Password]"/>
</connectionStrings>

And here is the general code:

Response.Write(ConfigurationManager.AppSettings["ImageFolder"]);
Response.Write(ConfigurationManager.ConnectionStrings["DBConnection"].ConnectionString);

Now lets use the expression....

<asp:Label ID="lblDBConnection" runat="server" Text='<%$ connectionStrings:DBConnection %>' />
<asp:Label ID="lblImageFolder" runat="server" Text='<%$ appSettings:ImageFolder %>' />

So simple!!!
The <%$ and %> tags are used to mark an expression that should be parsed by an ExpressionBuilder. Because of the prefix ConnectionStrings and appSettigs are already mapped to the particular ExpressionBuilder class that is responsible for parsing the expression; we dont need to do any extra afford.

Here are the default ExpressionBuilder classes provided by ASP.NET framework.

AppSettingsExpressionBuilderRetrieves values from the appSettings section of the web configuration file.

ConnectionStringsExpressionBuilderRetrieves values from the connectionStrings section of the web configuration file.

ResourceExpressionBuilderRetrieves values from resource files.

The ExpressionBuilder must always be used with control properties as I used in my example. You can create a custom ExpressionBuilder when none of the existing ExpressionBuilder classes do what you need, for this you must implement the ExpressionBuilder abstract class. Read More

Limitations of the XML Data Type

2008-07-31T22:39:00.000-07:00

Hi all,

I found the limitation of XML Data Type introduced in SQL Server 2005.

Although the XML datatype is treated like many other datatypes in SQL Server 2005, there are specific limitations to how it is used. These limitations are:

XML types cannot convert to text or ntext data types.

No data type other than one of the string types can be cast to XML.

XML columns cannot be used in GROUP BY statements.

Distributed partitioned views or materialized views cannot contain XML data types.

Use of the sql_variant instances cannot include XML as a subtype.

XML columns cannot be part of a primary or foreign key.

XML columns cannot be designated as unique.

Collation (COLLATE clause) cannot be used on XML columns.

XML columns cannot participate in rules.

The only built-in scalar functions that apply to XML columns are ISNULL and COALESCE. No other scalar built-in functions are supported for use against XML types.

Tables can have only 32 XML columns.

Tables with XML columns cannot have a primary key with more than 15 columns.

Tables with XML columns cannot have a timestamp data type as part of their primary key.

Only 128 levels of hierarchy are supported within XML stored in the database.

User Control and Javascript in UpdatePanel

2008-07-24T01:07:00.000-07:00

Hi All,

There is general practices where we require some javascript function while useing UpdatePanel; along with the User Control; and the more problamatic is when the User Contorl is dynamic.

Problem:
When we use UserControl which change the state of Ajax postback; sometimes we require some javascript which needs to be embaded after loading the UserControl and with this said I am using UpdatePanel. Means my code is in the UpdatePanel.

Solution:
Generally we are using following code to run any javascript in code behind


Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "key", "alert('hi');", true);

Now if you are using UpdatePanel then replace you above code with following code.


ScriptManager.RegisterClientScriptBlock(this, this.GetType(), "key", "alert('hi');", true);

Now you can see the alert saying 'hi' to you!!

Query operators evaluation

2008-07-23T03:00:00.000-07:00

Hi all,

Here is the order in which query operators are evaluated. There are 11 levels.

1. FROM
2. ON
3. JOIN
4. WHERE
5. GROUP BY
6. WITH{CUBE | ROLLUP}
7. HAVING
8. SELECT
9. DISTINCT
10. HAVING
11. TOP

First the query processor reads all the rows from the FROM the left table and apply the ON condition with the right table provided in JOIN.

If there are more JOINs the same is done for all the JOINs.

Then the WHERE clause is applied to filter rows.

Then GROUP BY is done

There WITH clause get evaluated followed by HAVING.

Then the columns are selected. (This is the reason why you cannot use a column alias in WHERE or GROUP BY)

Then DISTINCT clause applied

Then ORDER BY is processed...(This is the reason why you CAN use a column alias in the ORDER BY clause)

Then TOP clause get evaluated.
Refrence: SQL Server 2005: Query processing basics. An event presented by Vinod Kumar

Here is the screen-shot of the video captured during the event presented by Vinod Kumar in event.

OUTPUT CLAUSE (Transact-SQL)

2008-07-22T11:58:00.000-07:00

How to know your INSERT UPDATE or DELETE statement effect how much recoreds? Or what if I need the list of identity values which get generated by INSERT statements?

One way is before insert I should get the MAX ID; after sucessfull insert again I get the ID and select the ID which are in betwwen them, like...


DECLARE @MinId INT 2: DECLARE @MaxId INT 
SELECT @MinId = MAX(ID) from SearchResult 
INSERT INTO SearchResult(Keyword, Hits)
SELECT Keyword, Hits FROM TmpTable 
SELECT @MaxId = MAX(ID) from SearchResult 
SELECT ID FROM SearchResult WHERE ID > @MinID AND <= @MaxID

But the result will not always true, like in the world of multitasking, what if some other insert also take place??

Now? How can we get all the newly added or created identities?

The other and best way is using OUTPUT CLAUSE. Here we go...


DECLARE @IDTable Table
{
    Id BIGINT
} 
INSERT INTO SearchResult(Keyword, Hits)
OUTPUT INSERTED.ID INTO @IdTable

SELECT Keyword, Hits FROM TmpTable

The inserted IDs will be in magic table called INSERTED, and by using OUTPUT CLAUSE we can grab it and save it to temp table or temporary variable... from there we can select the newly added IDs, like..


SELECT ID FROM @IDTable

Ahmedabad SQL Server User Group

2008-07-20T21:26:00.000-07:00

Hello my dear friends,

I recently joined the user a user group, founded by Jacob Sebastian [MVP/Co-founder of Excellence Infonet, Ahmedabad]; the user group Ahmedabad SQL Server User Group is very fast growing and providing the knowledge which we either dont know or we are not willing to know. The group will have monthly event called "SQL Server Satureday", which provides developer/member to gain new knowledged shared by professional[s].

Recently on 19-July-2008, we have a very good and very interactive session, presented by Mr Pinal Dave [I hope you all know him very vell, visit his blogs http://blog.sqlauthority.com/ was mainly on best SQL Server best practices.

Read more

I was actively participed in the discussion/presentation on best; learns lots many things also added few practices.

Here is the group photo.

On my right side you can see the Mr. Pinal Dave and opposite to Mr Pinal, you can see Mr. Jacob Sebastian. And all the group member.

I request you to join the group and be part of such informative and intractive session.
Regards,
Imran

Overloading ToString Method of Enum

2008-07-15T03:20:00.000-07:00

Hello All,

The general scenario for using enum is to provide a way to restrict a variable to one of a fixed set of values.

Now at the same time we need the string value of enum, and by default we get what we right as the name of enum, like I created following enum


public enum Operation
{
    ChangePassword,
    EditProfile,
    SearchResult,
    Search
}

Now when I try to call ToString method will show the name of enum.


Operation operation = Operation.ChangePassword;
Console.Write(operation.ToString());

//It will show you
//ChangePassword

Now what if I want to show Change Password insted of ChangePassword?

We can do it by Extension methods which are introduced in C# 3.0, I created following Extension method which operates on my Operation enum. Here is the method.


public static string EnumToString(this Operation operation)
{
    switch (operation)
    {
        case Operation.ChangePassword:
            return "Change Password";
        case Operation.EditProfile:
            return "Edit Profile";
        case Operation.SearchResultL:
            return "Search Result";
        default :
            return operation.ToString();
    }
}

You see the switch case? I write the case for value which needs to show differently then name.


Operation operation = Operation.ChangePassword;
Console.Write(operation.EnumToString());

//this will show you what you needed
//Change Password

LoginView Control provided by .NET 2.0

2008-07-14T01:12:00.001-07:00

Its general prectices where we have to show some different layout when user is anonymous and different layout when user is authorized.

The .NET 2.0 provides the inbuild control, asp:LoginView; it will allow you to define the two different tamplets, one for anonymouse and another is for authorized user. Also it provides the the RoleGroups; using this you can also devide your authorized user template to one step down, means we can define the template based on Role too.

Here is the common template of asp:LoginView


<asp:LoginView runat="server" ID="loginView">
    <AnonymousTemplate>
        <table width="100%" border="0" cellspacing="0" cellpadding="0">
            <tr>
                <td class="top-menu">
                    <a href="#" title="">Login</a>
                </td>
            </tr>
        </table>
    </AnonymousTemplate>
    <LoggedInTemplate>
        <table width="100%" border="0" cellspacing="0" cellpadding="0">
            <tr>
                <td class="top-menu">
                    <a href="#" title="">Home</a>
                    <a href="#" title="">Change Password</a>
                    <a href="#" title="">Logout</a>
                </td>
            </tr>
        </table>
    </LoggedInTemplate>
</asp:LoginView>

SQL Server 2008 (KATMAI) - New Data Type: DATETIME2

2008-06-26T04:24:00.000-07:00

Check it out here

Using SP_EXECUTESQL

2008-06-24T22:38:00.000-07:00

What we can do with EXECUTE?

With EXECUTE you can build the complicate query which contains the replacement of parameters values run time. Just imagine the situation where you have only single query which needs to get run 3-4 times; each time the substitution is taking place?

Have a look at the following query; which requires running twice and also substituting the values.


/* Following by using EXEC*/

DECLARE @AcTypeID nvarchar(40)
DECLARE @SQLString NVARCHAR(500)
DECLARE @ParmDefinition NVARCHAR(500)
DECLARE @Gender int

/* Specify the parameter value*/
SET @AcTypeID = 1
set @Gender = 1

/* Build the SQL string*/
SET @SQLString = 'SELECT count(*) as TotalUserByAccount FROM [User] WHERE AccountTypeId = ' + CAST( @AcTypeID as NVARCHAR(10))
SET @SQLString = @SQLString + ' And Gender = ' + CAST(@Gender as NVARCHAR(1))

/* Execute the same string*/
EXEC(@SQLString)

/* Specify the parameter value*/
SET @AcTypeID = 5
set @Gender = 0

/* Build the SQL string AGAIN*/
SET @SQLString = 'SELECT count(*) as TotalUserByAccount FROM [User] WHERE AccountTypeId = ' + CAST( @AcTypeID as NVARCHAR(10))
SET @SQLString = @SQLString + ' And Gender = ' + CAST(@Gender as NVARCHAR(1))

/* Execute the same string*/
EXEC(@SQLString)

So this is the first problem with EXECUTE?command, now next problem; it does not generate execution plans which are more likely to be reused by SQL Server. So the performance is not good if we have such query execute frequent.

Now, using SP_EXECUTESQL we can overcome both of above mentions problem. SP_EXECUTESQL gives you the possibility to use parameterized statements, EXECUTE does not. Parameterized statements gives no risk to SQL injection and also gives advantage of cached query plan. I will show you the cached query plan too.

First here is the query.


/* Now lets use sp_executesql */

DECLARE @AcTypeID nvarchar(40)
DECLARE @Gender nvarchar(40)
DECLARE @SQLString NVARCHAR(500)
DECLARE @ParmDefinition NVARCHAR(1000)

/* Build the SQL string once. */
SET @SQLString = N'SELECT count(*) as TotalUserByAccount FROM [User] WHERE AccountTypeId = @paramAcTypeID and Gender = @paramGender'

/* Specify the parameter format once. */
SET @ParmDefinition = N'@paramAcTypeID bigint, @paramGender int'

/* Set the param value */
set @Gender = 1
SET @AcTypeID = 1

/* Execute the query */
EXECUTE sp_executesql @SQLString, @ParmDefinition,
                      @paramAcTypeID = @AcTypeID, @paramGender = @Gender

/* set only param value again*/
set @Gender = 0
SET @AcTypeID = 5

/* Execute the query */
EXECUTE sp_executesql @SQLString, @ParmDefinition,
                      @paramAcTypeID = @AcTypeID, @paramGender = @Gender

Now let’s check our Cache Objects of SQL Server, [I used DBCC FREEPROCCACHE first so its cleare all the cache plan and run the query]

Now the thing that I like most; getting OUTPUT variable by using SP_EXECUTESQL, here are the code for getting variable as OUTPUT.


/* Variable declaration */
DECLARE @UserID uniqueidentifier
DECLARE @UserName nvarchar(40)
DECLARE @SQLString NVARCHAR(500)
DECLARE @ParmDefinition NVARCHAR(1000)

/* Build the SQL string*/
SET @SQLString = N'SELECT @paramUserID = UserID FROM [User] WHERE FavUserName = @paramUserName'

/* Specify the parameter format once. */
set @ParmDefinition = N'@paramUserName nvarchar(40), @paramUserID uniqueidentifier output'

/* Execute the string with the parameter value. */
EXECUTE sp_executesql @SQLString, @ParmDefinition,
            @paramUserName = 'imran786', @paramUserID = @UserID OUTPUT

/* Get the output value */
print @UserID

One of the limitations of SP_EXECUTESQL in SQL Server 2000 was that the input code string was practically limited to 4000 characters. This limitation is not relevant anymore because you can now provide sp_executesql with an NVARCHAR(MAX) value as input. Note that SP_EXECUTESQL supports only Unicode input—unlike EXEC which supports both regular character and Unicode input.

Read more...