Catching an exception and clearing it before ELMAH gets it

Question

I have a problem where I have an exception being thrown that I am capturing in Global.asax. As part of this exception handling I redirect the user to a specific page because of this exception.

I also have ELMAH error handling with the email module plugged in. I do not want to receive emails for this exception. I also don't want to add this type of exception to ELMAHs ignore list, in case I want to do granular work around the exception (i.e., only if it matches certain properties, happens on certain pages)

I want to:

• write an Application_OnError that redirects a user to a page (I know how to do this part, more for procedure I've left it here)
• in the Application_OnError stop ELMAH from receiving this error after I've caught it

I am currently calling Server.ClearError() inside my App_OnError method, but am still receiving these emails.

Answer 1

As per the ELMAH documentation

I put leave my Application_OnError method in my Global.asax but I also add the following global methods:

void ErrorLog_Filtering(object sender, ExceptionFilterEventArgs args)
{
    Filter(args);
}

void ErrorMail_Filtering(object sender, ExceptionFilterEventArgs args)
{
    Filter(args);
}

void Filter(ExceptionFilterEventArgs args)
{
    if (args.Exception.GetBaseException() is HttpRequestValidationException)
    {
        args.Dismiss();
    }
}

What this does is dismiss the ELMAH exception if it is the type that matches what I want - in my case the HttpRequestValidationException.

The ErrorMail_Filtering method is only required if you have the error mail filter turned on - which I do.