在Try / Catch Block中使用Response.Redirect（url）

Question

If my response to errors in a try/catch block is to redirect users to an error page, the try/catch block behaves as if there was an error when there was not. If I change it to do something else, the code works fine.

Example:

try
{
    //do this SQL server stuff
}
catch
{
   Response.Redirect(error.htm)
   //Change this to lblErr.Text = "SQL ERROR"; and the code in try works fine.
}

From another post I learned there was a boolean overload to the Response.Redirect() method. I tried both true and false and the try/catch block still behaved as if there were an error.

What's the deal?

Answer 1

When you Response.Redirect, that throws a ThreadAbortException. So to get the outcome you are describing you'll want to mod your code as follows:

try  
{
   // Do some cool stuff that might break
}
catch(ThreadAbortException)
{

}
catch(Exception e)
{
  // Catch other exceptions
  Response.Redirect("~/myErrorPage.aspx");
}

Answer 2

Response.Redirect("url");

By design this will terminate the calling thread by throwing an exception.

Response.Redirect("url", false);

Will prevent the exception from being thrown, however will allow the code to continue executing.

Using

Response.Redirect("url", false);
HttpContext.Current.ApplicationInstance.CompleteRequest();

Will redirect the user and stop execution without throwing an exception.

Answer 3

You should use the HandleError attribute.

[HandleError]
public ActionResult Foo(){
    //...

    throw new Exception(); // or code that throws execptions

    //...
}

That way exceptions automatically cause redirection to an error page.

Answer 4

你忘了引号和分号：

Response.Redirect("error.htm");