Unable to evaluate expression because the code is optimized or a native frame is on top of the call stack

Solution 1:

Request.Redirect(url,false);

false indicates whether execution of current page should terminate.

Solution 2:

Make second argument of Response false as shown below.

Response.Redirect(url,false);

Solution 3:

Resolution

To work around this problem, use one of the following methods:

• For Response.End, call the HttpContext.Current.ApplicationInstance.CompleteRequest() method instead of Response.End to bypass the code execution to the Application_EndRequest event.

• For Response.Redirect, use an overload, Response.Redirect(String url, bool endResponse) that passes false for the endResponse parameter to suppress the internal call to Response.End. For example: Response.Redirect ("nextpage.aspx", false); If you use this workaround, the code that follows Response.Redirect is executed.

• For Server.Transfer, use the Server.Execute method instead.

Symptoms

If you use the Response.End, Response.Redirect, or Server.Transfer method, a ThreadAbortException exception occurs. You can use a try-catch statement to catch this exception.

Cause

The Response.End method ends the page execution and shifts the execution to the Application_EndRequest event in the application's event pipeline. The line of code that follows Response.End is not executed.

This problem occurs in the Response.Redirect and Server.Transfer methods because both methods call Response.End internally.

Status

This behavior is by design.

Properties

Article ID: 312629 - Last Review: August 30, 2012 - Revision: 4.0

Applies to

• Microsoft ASP.NET 4.5
• Microsoft ASP.NET 4
• Microsoft ASP.NET 3.5
• Microsoft ASP.NET 2.0
• Microsoft ASP.NET 1.1
• Microsoft ASP.NET 1.0

Keywords: kbexcepthandling kbprb KB312629

Source: PRB: ThreadAbortException Occurs If You Use Response.End, Response.Redirect, or Server.Transfer

Solution 4:

In a bug I was investigating there was a Response.Redirect() and it was executing in an unexpected location (read: inappropriate location - inside a member property getter method).

If you're debugging a problem and experience the "Unable to evaluate expression..." exception:

1. Perform a search for Response.Redirect() and either make the second parameter endResponse = false, or
2. Temporarily disable the redirect call.

This was frustrating as it would appear to execute the Redirect call before the "step through" on the debugger had reached that location.

Solution 5:

Please check this link for the reason behind this issue and solution for the error:

http://support.microsoft.com/kb/312629/EN-US/

Microsoft Support Article:

PRB: ThreadAbortException Occurs If You Use Response.End, Response.Redirect, or Server.Transfer Print Print Email Email

To work around this problem, use one of the following methods: For Response.End, call the HttpContext.Current.ApplicationInstance.CompleteRequest method instead of Response.End to bypass the code execution to the Application_EndRequest event.

For Response.Redirect, use an overload, Response.Redirect(String url, bool endResponse) that passes false for the endResponse parameter to suppress the internal call to Response.End.

For example: Response.Redirect ("nextpage.aspx", false);

If you use this workaround, the code that follows Response.Redirect is executed. For Server.Transfer, use the Server.Execute method instead.