Show Custom Exception Message

Question

I'm trying to show a custom exception message while preserving the inner exception.

Here is my sample code:

public class Class1
{
public Class1()
{
 try
 {
 throw new WebException("Initial Exception");
 }
 catch (WebException we)
 {
 throw new myException("Custom Message", we);
 }
}
}
public class myException : WebException
{
public myException(string msg, WebException e) : base(msg, e) { }
}

When I run this code it shows me the custom message in the debugger: Screenshot1

yet still sends the innerexception message to the client: Screenshot2

What am I doing wrong here? How do I preserve the inner exception while showing my own custom message?

• Chris Sinclair: Notice that it's still showing your custom myException information. I'm guessing this is a "feature" of ASP.NET's server that shows the inner exception data first as the source originator of the problem. I imagine, perhaps, that this is for convenience for server-side debugging. Possibly there's a server config option to control this but I don't know.
• Jesse C. Slicer: "You should not define new exception classes derived from ApplicationException; use Exception instead. In addition, you should not write code that catches ApplicationException." - Microsoft
• Jesse C. Slicer: Also, I think you may be wanting throw; rather than throw e; as your final Exception catch handler - it'll preserve the stack information while what you have will not.
• Greg: @JesseC.Slicer, I'm just using this code an an example, I didn't have any luck with throw; because I still want to preserve the initial exception

Answer 1

The way to customise the message the user sees is to provide a custom error page.

http://support.microsoft.com/kb/306355

Answer 2

I suspect it's because the ApplicationException isn't being effectively handled and the catch block throws an exception which is then being picked up as a base Exception. The debugger is then listing both exceptions.

I think this will give the behaviour you're after (I've written as a console app)

using System;
namespace ConsoleApplication2
{
 class Program
 {
 static void Main(string[] args)
 {
 myException exception;
 try
 {
 throw new ApplicationException("Initial Exception");
 }
 catch (ApplicationException e)
 {
 exception = new myException("Custom Message", e);
 }
 catch (Exception e)
 {
 throw e;
 }
 if (exception != null)
 {
 throw exception;
 }
 }
}
}
public class myException : ApplicationException
{
public myException(string msg, ApplicationException e) : base(msg, e) { }
}