Question

I started a new WPF project in VS2008 and then added some code to trap DispatcherUnhandledException. Then I added a throw exception to Window1 but the error is not trapped by the handler. Why?

   public App()     {         this.DispatcherUnhandledException += new DispatcherUnhandledExceptionEventHandler(App_DispatcherUnhandledException);      }      void App_DispatcherUnhandledException(object sender, DispatcherUnhandledExceptionEventArgs e)     {         System.Windows.MessageBox.Show(string.Format('An error occured: {0}', e.Exception.Message), 'Error');         e.Handled = true;     }   void Window1_MouseDown(object sender, MouseButtonEventArgs e)     {         throw new NotImplementedException();     } 

Answer 1

This can happen because of the way you have the debugger handling exceptions — Debug/Exceptions… should allow you to configure exactly how you want it handled.