Question

I’m using the following code to display unhandled exceptions in a WPF application:

        public MyApplication() {
            this.DispatcherUnhandledException += (o, e) => {
                var exceptionMessage = new ExceptionWindow();
                exceptionMessage.ExceptionMessage.Text = e.Exception.Message;
                exceptionMessage.ExceptionCallStack.Text = e.Exception.StackTrace;
                exceptionMessage.ExceptionInnerException.Text = e.Exception.InnerException.Message;
                exceptionMessage.WindowStartupLocation = WindowStartupLocation.CenterScreen;
                exceptionMessage.WindowStyle = WindowStyle.ToolWindow;
                exceptionMessage.ShowDialog();
                e.Handled = true;
                Shell.Close();
            };
        }

Turns out that I have an exception during the instantiation of the application, so the app constructor is never executed.

A simple way to reproduce it (with a different exception) is by introducing an extra “<” before some tag in your app’s configuration file and run it.

A useless error message like that appears before the application constructor get called.
alt text http://srtsolutions.com/cfs-filesystemfile.ashx/__key/CommunityServer.Blogs.Components.WeblogFiles/mikewoelmer/ExceptionWPF1_5F00_1C1F39AA.jpg

Does anyone know how to catch such kind of exceptions?

Remark: I’m using Caliburn and my application extends CaliburnApplication.

Answer 1

Okay. I solved the problem by doing the following:

• Change the Build Action of the App.xaml file from ApplicationDefinition to Page.

• Create a new class like following:

    public class AppStartup {
        [STAThread]
        static public void Main(string[] args) {
            try {
                App app = new App();
                app.InitializeComponent();
                app.Run();
            }
            catch (Exception e) {
                MessageBox.Show(e.Message + "\r\r" + e.StackTrace, "Application Exception", MessageBoxButton.OK, MessageBoxImage.Error);
            }
        }
    }

It replaces the generated App.g.cs Main method by this one, so we have a chance to catch the exceptions.