WPF global exception handler [duplicate]

Answer 1

You can handle the AppDomain.UnhandledException event

EDIT: actually, this event is probably more adequate: Application.DispatcherUnhandledException

Answer 2

A quick example of code for Application.Dispatcher.UnhandledException:

public App() {
    this.Dispatcher.UnhandledException += OnDispatcherUnhandledException;
}

void OnDispatcherUnhandledException(object sender, System.Windows.Threading.DispatcherUnhandledExceptionEventArgs e) {
    string errorMessage = string.Format("An unhandled exception occurred: {0}", e.Exception.Message);
    MessageBox.Show(errorMessage, "Error", MessageBoxButton.OK, MessageBoxImage.Error);
    // OR whatever you want like logging etc. MessageBox it's just example
    // for quick debugging etc.
    e.Handled = true;
}

I added this code in App.xaml.cs

Answer 3

To supplement Thomas's answer, the Application class also has the DispatcherUnhandledException event that you can handle.

Answer 4

You can trap unhandled exceptions at different levels:

1. AppDomain.CurrentDomain.UnhandledException From all threads in the AppDomain.
2. Dispatcher.UnhandledException From a single specific UI dispatcher thread.
3. Application.Current.DispatcherUnhandledException From the main UI dispatcher thread in your WPF application.
4. TaskScheduler.UnobservedTaskException from within each AppDomain that uses a task scheduler for asynchronous operations.

You should consider what level you need to trap unhandled exceptions at.

Deciding between #2 and #3 depends upon whether you're using more than one WPF thread. This is quite an exotic situation and if you're unsure whether you are or not, then it's most likely that you're not.

Answer 5

A complete solution is here

it's explained very nice with sample code. However, be careful that it does not close the application.Add the line Application.Current.Shutdown(); to gracefully close the app.

Answer 6

In addition to the posts above:

Application.Current.DispatcherUnhandledException

will not catch exceptions that are thrown from a thread other than the main thread. You have to catch those exceptions on the same thread they are thrown. But if you want to Handle them on your global exception handler you can pass it to the main thread:

 System.Threading.Thread t = new System.Threading.Thread(() =>
    {
        try
        {
            ...
            //this exception will not be catched by 
            //Application.DispatcherUnhandledException
            throw new Exception("huh..");
            ...
        }
        catch (Exception ex)
        {
            //But we can handle it in the throwing thread
            //and pass it to the main thread wehre Application.
            //DispatcherUnhandledException can handle it
            System.Windows.Application.Current.Dispatcher.Invoke(
                System.Windows.Threading.DispatcherPriority.Normal,
                new Action<Exception>((exc) =>
                    {
                      throw new Exception("Exception from another Thread", exc);
                    }), ex);
        }
    });