How can I get WinForms to stop silently ignoring unhandled exceptions?

Question

This is getting extremely irritating. Right now I have a winforms application, and things were not working right, but no exceptions were being thrown as far as I could tell

Answer 1

An easy fix is not to run under the debugger.

The debugger is masking the exception for some reason. If you run your app normally (Ctrl+F5), you'll get the usual "Unhandled exception has occurred in your application... Continue/Quit?" dialog.

Answer 2

Having experienced this often and identified the issue regarding 64 bit OS and the Form.Load event, I always just make a point of doing all my start up functions in the Form.Shown event. For all practical purposes this is the same thing (aside from a few rare, exceptional circumstances), and the JIT message is produced in the Shown event.

Answer 3

In your Program.cs' Main function you should also ensure that you've wrapped your call to open the form in a try/catch. Additionally use the AppDomain.UnhandledException to catch exceptions. We also add Application.ThreadException too.

I believe the following will give you hooks into all the exceptions that can be thrown...

static void Main()
{
    try
    {
        System.Windows.Forms.Application.SetUnhandledExceptionMode(UnhandledExceptionMode.CatchException);
        System.Windows.Forms.Application.ThreadException += new System.Threading.ThreadExceptionEventHandler(OnGuiUnhandedException);
        AppDomain.CurrentDomain.UnhandledException += OnUnhandledException;

        var form = new MainForm();
        form.ShowDialog();
    }
    catch (Exception e)
    {
        HandleUnhandledException(e);
    }
    finally
    {
        // Do stuff
    }
}

private static void HandleUnhandledException(Object o)
{
    // TODO: Log it!
    Exception e = o as Exception;

    if (e != null)
    {

    }
}

private static void OnUnhandledException(Object sender, UnhandledExceptionEventArgs e)
{
    HandleUnhandledException(e.ExceptionObject);
}

private static void OnGuiUnhandedException(object sender, System.Threading.ThreadExceptionEventArgs e)
{
    HandleUnhandledException(e.Exception);
}

Answer 4

Try the following.

• Handle exceptions in your main application entry point.
• Also, manage unhandled thread exceptions using a ThreadExceptionEventHandler

This is the code snippet:

[STAThread]
public static void Main(string[] args)
{
    try
    {
        Application.ThreadException += new ThreadExceptionEventHandler(Application_ThreadException);
        //your program entry point
    }
    catch (Exception ex)
    {
       //manage also these exceptions
    }
}

private void Application_ThreadException(object sender, ThreadExceptionEventArgs e)
{
    ProcessException(e.Exception);
}