UnhandledException & ThreadException

When developing a windows/console application using .Net, it is recommended to catch AppDomain.CurrentDomain.UnhandledException and Application.ThreadException. If there are some uncaught exceptions raised in a app-domain, the system default handler will report the exception and terminates the application by default, and if raised in a thread, the thread may be blocked. Catching UnhandledException and ThreadException events provides us a way of creating robust applications.

The following code segements demonstrate how to make use of the two events:

 1 static void Main()
 2 {
 3   try {
 4     // Setup unhandled exception handlers
 5     //
 6     AppDomain.CurrentDomain.UnhandledException +=
 7     new UnhandledExceptionEventHandler(OnUnhandledException);
 8 
 9     // Unhandled Forms exceptions will be delivered to our ThreadException handler
10     //
11     Application.ThreadException +=
12     new System.Threading.ThreadExceptionEventHandler(AppThreadException);
13     .
14   }
15   catch( Exception e ) {  }
16 }
17 
18 /// <summary>
19 /// CLR unhandled exception
20 /// </summary>
21 private static void OnUnhandledException(Object sender, UnhandledExceptionEventArgs e)
22 {
23   HandleUnhandledException(e.ExceptionObject);
24 }
25 
26 /// <summary>
27 /// Displays dialog with information about exceptions that occur in the application.
28 /// </summary>
29 private static void AppThreadException(object source, System.Threading.ThreadExceptionEventArgs e)
30 {
31   HandleUnhandledException(e.Exception);
32 }
33 
34 static void HandleUnhandledException(Object o)
35 {
36   Exception exp = o as Exception;
37   MessageBox.Show(exp.Message, "Application Error", MessageBoxButtons.OK, MessageBoxIcon.Stop);
38 
39   Application.Exit(); // Shutting down
40 }