Validation (): Element "elementname" is not supported in ASP.NET WebForms in Visual Studio 2008 and Visual Studio 2005

Sometimes application will compile and run properly but in IDE you got following warning message on each control.

"Validation ():Element is not supported"

Solution:

Visual Studio 2008 - Delete all files from below location in your machine,

1:- C:\Documents and Settings\[Username]\Application Data\Microsoft\VisualStudio\9.0\ReflectedSchemas

2:- C:\Documents and Settings\[Username]\Application Data\Microsoft\VisualStudio\9.0\ReflectedTypeLibs

Visual Studio 2005 - Delete all files from below location in your machine,

1:- C:\Documents and Settings\[Username]\Application Data\Microsoft\VisualStudio\8.0\ReflectedSchemas

2:- C:\Documents and Settings\[Username]\Application Data\Microsoft\VisualStudio\8.0\ReflectedTypeLibs

Thanks

: Could not load type 'System.Web.UI.ScriptReferenceBase' from assembly 'System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3

Installed Microsoft Framework 3.5 SP1.

Error while trying to run project: Unable to start debugging on the web server. The project is not configured to be debugged.

Error: Error while trying to run project: Unable to start debugging on the web server. The project is not configured to be debugged.

Cause: Either debug is not enabled in your web.config (OR) For some reasons IIS is not considering your web application as a virtual directory. Instead it is considering it to be a normal folder.

Solution 1:

Step 1: Open the web.config
Step 2: If debug is set to "false" change it to "True".

For example: In web.config I have a line like this I would change it to

If at all this doesn't work. Try out the next solution.

Solution 2:

1.From the Start menu, choose Programs, then Administrative Tools, and click Internet Information Services.

2.In the Internet Information Services dialog box, click the tree control for your machine, open the Web Sites folder, and find your web site.

3.Right-click Web Site and choose Properties.

4.In the Web Site Properties window, select the Directory tab.

5.Under Application Settings, look for the Remove or Create button. If the button says Remove, your website is already configured as an application. If the button says Create, click the button to configure your website as an application.

6.Click OK.

If it also doesn't work, try the next solution.

Solution 3:

If you are running Visual Studio 2003 (or ASP.NET v1.1) you should setup IIS to use ASP.NET v1.1 and not ASP.NET v2.0

May be you have installed .NET framework 1.1 as well as 2.0 in your box and trying to run an application via VS.NET 2003. If so, then do the following:

Step 1: Start >> Run >> inetmgr
Step 2: Navigate to the virtual directory of the project which is throwing this error.
Step 3: Right click on the virtual directory and choose "Properties"
Step 4: Choose the tab ASP.NET
Step 5: The first dropdown would read "ASP.NET Version", choose 1.1.4322


Solution 4 :

1. go to the C:\WINNT\Microsoft.NET\Framework\
2. and run aspnet_regiis.exe /i
That's it. Hope this helps.

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible.

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)



Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.


Exception Details: System.Data.SqlClient.SqlException: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)


Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Solution: viewview Solution

Cannot create/shadow copy [Project File Name] when that file already exists.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.IO.FileLoadException: Cannot create/shadow copy 'Test.UI' when that file already exists.


Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.


Assembly Load Trace: The following information can be helpful to determine why the assembly 'Test.UI' could not be loaded.


WRN: Assembly binding logging is turned OFF.
To enable assembly bind failure logging, set the registry value [HKLM\Software\Microsoft\Fusion!EnableLog] (DWORD) to 1.
Note: There is some performance penalty associated with assembly bind failure logging.
To turn this feature off, remove the registry value [HKLM\Software\Microsoft\Fusion!EnableLog].


Solution : visit View Solution

Changing the default browser used in VS 2008 and Visual Web Developer

I have seen a few people ask if it is possible to change what browser is launched and used when running web applications in VS 2008 and Visual Web Developer (for example:Chrome, Firefox instead of IE). It is an easy way to configure this.

Below is steps:

1) Right click on a .aspx page in your solution explorer

2) Select the "browse with" context menu option

3) In the dialog you can select or add a browser. If you want Firefox in the list, click "add" and point to the firefox.exe filename

4) Click the "Set as Default" button to make this the default browser when you run any page on the site.

Note that there is also an optional drop-down at the bottom of the dialog that lets you select the default browser window size when loading. You can choose 800x600 or 1024x768 if you want to visualize what the site will look like for people using those screen resolutions. This works for both IE and FireFox (and probably other browsers too -- those just happened to be the two I checked).

Hope this helps,
www.interviewsworld.com

New feature in Visual Studio 2008

some new features are-.

1-Improved Designer (i.e.WYSIWYG)
2-modern CSS editing options
3-enhanced java script debugging and development support
4-visual studio 2008 can target web applications to the .NET 2.0 , .NET 3.0 and .NET 3.5 environment.

To Know more

http://www.interviewsworld.com/Q_326_new-feature-in-visual-studio-2008.aspx

Thanks