We've been using unhandled exceptions for ages and we register both Application.Current.DispatcherUnhandledException and AppDomain.CurrentDomain.UnhandledException
but the following repro case using Drop Event handler does not trigger any unhandled exception handler.
When I throw the exception from UI or task, some handler will be triggered, but form the documentation I don't comprehend why no handler is triggered in my scenario below as I would expect the Dispatcher calling DispatcherUnhandledException
This is VS 2015 with .net 4.5.2
Repro WPF code is very simple, only AllowDrop and Drop handler. Note: The handlers are registered in the window ctor, same behaviour when doing that in app.xaml.cs.
Just drag & drop any file into it, a message box should appear but it does not.
<Window x:Class="unhandledex_wpf.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525" AllowDrop="True" Drop="MainWindow_OnDrop">
<Grid>
</Grid>
</Window>
Code behind:
using System;using System.Threading.Tasks;using System.Windows;
namespace unhandledex_wpf
{
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
Application.Current.DispatcherUnhandledException += ( sender, args ) => MessageBox.Show( "Exception" );
AppDomain.CurrentDomain.UnhandledException += ( sender, args ) => MessageBox.Show( "Exception" );
TaskScheduler.UnobservedTaskException += ( sender, args ) => MessageBox.Show( "Exception" );
// works Task.Run( ( )=> { throw new Exception( "foo" ); } );
}
private void MainWindow_OnDrop( object sender, DragEventArgs e )
{
throw new NotImplementedException("Catch me");
}
}
}
