Exceptions debugging with async and UWP

Question

I'm working on the UWP application. And I'm using async/await a lot. Always when an exception occurs in my code the debugger set break in App.g.i.cs

#if DEBUG && !DISABLE_XAML_GENERATED_BREAK_ON_UNHANDLED_EXCEPTION
            UnhandledException += (sender, e) =>
            {
                if (global::System.Diagnostics.Debugger.IsAttached) global::System.Diagnostics.Debugger.Break();
            };
#endif

But I want to see the line when the exception occured. How to achieve that behavior ?

You would have to handle the exception where it is thrown. For instance a try catch? Not sure what answer you are looking for here — default, May 20 '16 at 14:33
@Default, the problem is I don't know where it is thrown and I want debuger to show it for me )) — IL_Agent, May 20 '16 at 15:30
@Janak, no, NullReferenceException for examle, in a view model — IL_Agent, May 20 '16 at 15:30
Possible duplicate of [Visual Studio: How to break on handled exceptions?](http://stackoverflow.com/questions/116896/visual-studio-how-to-break-on-handled-exceptions) — default, May 20 '16 at 16:04
or [this](http://stackoverflow.com/questions/1698154/force-break-on-any-exception-thrown-in-program) or [this](http://stackoverflow.com/questions/11183099/how-to-make-visual-studio-break-only-on-unhandled-exceptions) or [this](http://stackoverflow.com/questions/5597421/breakpoint-on-an-exception-in-visual-studio) — default, May 20 '16 at 16:06

Petter Hesselberg · Accepted Answer · 2016-05-20T14:48:12.797

Add the following method to your App class:

private static void UnhandledError(object sender, UnhandledErrorDetectedEventArgs eventArgs)
{
    try
    {
        // A breakpoint here is generally uninformative
        eventArgs.UnhandledError.Propagate();
    }
    catch (Exception e)
    {
        // Set a breakpoint here:
        Debug.WriteLine("Error: {0}", e);
        throw;
    }
}

In your App constructor:

public UnitTestApp()
{
    CoreApplication.UnhandledErrorDetected += UnhandledError;

    // ...and any other initialization.
    // The InitializeComponent call just sets up error handlers,
    // and you can probably do without in the case of the App class.

    // This can be useful for debugging XAML:
    DebugSettings.IsBindingTracingEnabled = true;
    DebugSettings.BindingFailed +=
        (sender, args) => Debug.WriteLine(args.Message);

}

There are still cases where you don't get a good stack trace, but this is often helpful.

Another approach is to break when an exception is thrown (via Debug, Windows, Exception Settings).

Thank you, it's very usefull ! But why debugger can't set break to expected line ? — IL_Agent, May 20 '16 at 15:44
Tell Visual Studio to break when (all or any specific) exception is thrown. The stack trace will provide the method, but not thw line. — Petter Hesselberg, May 20 '16 at 16:02
Yes ! I've checked all Common Language Runtime Exceptions and not it's working ! Thank you. — IL_Agent, May 20 '16 at 16:42

Exceptions debugging with async and UWP

1 Answers1