c# - Async exception handling with void

Question

I'm using Async CTP to write an IO heavy console app. But I'm having problems with exceptions.

public static void Main()
{
   while (true) {
     try{
         myobj.DoSomething(null);
     }
     catch(Exception){}
     Console.Write("done");
     //...
   }
}

//...
public async void DoSomething(string p)
{
   if (p==null) throw new InvalidOperationException();
   else await SomeAsyncMethod();
}

And the following happens: "done" gets written to the console, then I get the exception in the debugger, then I press continue my program exists.
What gives?

Answer 1

If you give your Console application an async-compatible context (e.g., AsyncContext (docs, source) from my AsyncEx library), then you can catch exceptions that propogate out of that context, even from async void methods:

public static void Main()
{
  try
  {
    AsyncContext.Run(() => myobj.DoSomething(null));
  }
  catch (Exception ex)
  {
    Console.Error.WriteLine(ex.Message);
  }
  Console.Write("done");
}

public async void DoSomething(string p)
{
  if (p==null) throw new InvalidOperationException();
  else await SomeAsyncMethod();
}