Question

I have a problem in a WPF application. I wrote this code:

public partial class App : Application
{
    public App()
    {
        AppDomain.CurrentDomain.UnhandledException += new 
            UnhandledExceptionEventHandler(MyHandler);
    }

    void MyHandler(object sender, UnhandledExceptionEventArgs e)
    {
        Exception exception = e.ExceptionObject as Exception;
        MessageBox.Show(exception.Message, "ERROR",
                        MessageBoxButton.OK, MessageBoxImage.Error);
    }

    ...
}

but when a unhandled exception happens, a lot of MessageBox appear to the screen (the exception happens in a timed routine) and after closing one of them, Windows signals that there is an unhandled exception.

How can I avoid multiple MessageBoxes?
How can I avoid the message of an unhandled exception?
How can I terminate the application after the exception?
As you can easily suppose, I would like to show a message (but only one) with my MessageBox and then terminate the application without any other message.

In a previous question related to this argument, Kyle Rozendo told me to use DispatcherUnhandledException. Is it necessary or the code I written is sufficient?

Thank you.

Answer 1

You can avoid multiple messageboxes by initializing a static boolean firstTime to true and use the code within the Exception handler:

void MyHandler(object sender, UnhandledExceptionEventArgs e) 
{ 
   if (firstTime){
        Exception exception = e.ExceptionObject as Exception; 
        MessageBox.Show(exception.Message, "ERROR", 
                        MessageBoxButton.OK, MessageBoxImage.Error); 
        firstTime = false;
   }else{
        // Now kill the process....
   }
} 

To terminate the process do this, within the MyHandler:

System.Diagnostics.Process proc = System.Diagnostics.Process.GetCurrentProcess();
proc.Kill();