Debugger not breaking/stopping for exceptions in async method

Sebastian Krysmanski picture Sebastian Krysmanski · Aug 6, 2013 · Viewed 14.6k times · Source

When a debugger is attached to a .NET process, it (usually) stops when an unhandled exception is thrown.

However, this doesn't seem to work when you're in an async method.

The scenarios I've tried before are listed in the following code:

class Program
{
    static void Main()
    {
        // Debugger stopps correctly
        Task.Run(() => SyncOp());

        // Debugger doesn't stop
        Task.Run(async () => SyncOp());

        // Debugger doesn't stop
        Task.Run((Func<Task>)AsyncTaskOp);

        // Debugger stops on "Wait()" with "AggregateException"
        Task.Run(() => AsyncTaskOp().Wait());

        // Throws "Exceptions was unhandled by user code" on "await"
        Task.Run(() => AsyncVoidOp());

        Thread.Sleep(2000);
    }

    static void SyncOp()
    {
        throw new Exception("Exception in sync method");
    }

    async static void AsyncVoidOp()
    {
        await AsyncTaskOp();
    }

    async static Task AsyncTaskOp()
    {
        await Task.Delay(300);
        throw new Exception("Exception in async method");
    }
}

Am I missing something? How can I make the debugger to break/stop on the exception in AsyncTaskOp()?

Answer

Stephen Cleary picture Stephen Cleary · Aug 6, 2013

Under the Debug menu, select Exceptions.... In the Exceptions dialog, next to the Common Language Runtime Exceptions line check the Thrown box.