Question

I am using .net framework 4.0, plain asp.net and working with webform. Currently I having a base class to handle all parameter passing and redirect. I wonder is it possible to write a base class to handle nullRefeerenceException from all pages in once, lets say redirect end user to somewhere or display particular error message.

Scenario: For example, some pages must come along with parameter, if no parameter captured, I would like to redirect them to somewhere.

Answer 1

You can try to control the ProcessRequest. You need to test it to see if can do the work you ask for, but this is a good point to capture all errors of your page.

public override void ProcessRequest(HttpContext context)
{
    try
    {
        base.ProcessRequest(context);
    }
    catch (Exception x)
    {
        // handle here your error from the page...
    }
}

Some more notes

I was use this code on one critical page, but I do not use it for all my page. Even tho can capture the errors, some times you can not do nothing else here other than throw again the final error, so end up that is better to log your unknown and unhandled errors from globa.asax Application_Error, and on page make sure that you use try/catch to handle them where they happens.

After some think maybe is not good practice to use it. Good practice is to use try/catch in the place that you may have throws and not a general one like that.

Last

You also get throw error here when the user close the connection before the end of the render, but if you log the errors you get the same on Application_Error – this is not a page error.

    Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> 
   System.Web.HttpException: The remote host closed the connection. 
   The error code is 0x80072746.