Support Global Exception Handling Mechanism for .NET MAUI

[TanayParikh]

Discussed in #653

^{Originally posted by AmSmart April 5, 2021}
With the new host model in .NET Maui, will we get a straightforward way of catching exceptions?

Currently this is possible in WPF/WinForms via:

AppDomain.CurrentDomain.UnhandledException += (sender, error) =>
{
    MessageBox.Show(text: error.ExceptionObject.ToString(), caption: "Error");
};

The ask of this issue is to enable AppDomain.CurrentDomain.UnhandledException for MAUI based applications to support a global exception handling mechanism.

I looked into the Windows MAUI WinUI3 end of things, and there appears to be a potential bug with the DispatcherQueue which prevents the application from being sent to the AppDomain.CurrentDomain.UnhandledException: microsoft/microsoft-ui-xaml#5221

cc/ @hartez @mattleibow

Blazor Hybrid

Cross linking dotnet/aspnetcore#40765 which handles the case of WPF/WinForms in Blazor Hybrid. If there's a canonical way to do global exception handling (like we have in WinForms/WPF), we need to ensure .NET MAUI Blazor Hybrid is able to integrate with it directly.

Blazor Hybrid MAUI tracking issue: #4441

• WPF/WinForms Blazor WebView Exception Handling aspnetcore#40765
• App.UnhandledException doesn't catch exceptions from other threads. microsoft/microsoft-ui-xaml#5221
• [Blazor webview] Exception handling for blazor webview #4441
• MAUI: enable AppDomain.CurrentDomain.UnhandledException for MAUI based applications to support a global exception handling mechanism

[emorell96]

Any update on this now that MAUI is so close to GA?

[kfrancis]

Ugh! Trying to port, having a hard time because I can't see what's going wrong here:

We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.

[ericgrantholland]

Any updates here? Will this be included in the .NET 8 release of MAUI?

This is a huge blocker for anyone using MAUI for real/prod applications. I'm using Blazor Hybrid and the app completely hangs when an error occurs with no way to inform the user of anything going on. I do see that AppDomain.CurrentDomain.FirstChanceException fires, but no other events get fired after that, at least to my knowledge.

A bit disappointing that this isn't considered high-priority considering MAUI is no longer in preview.