Throwing an exception from a BackgroundWorker which calls an async. method (Webrequest)

Question

Hi,

• My main application creates a new BackgroundWorker X
• the DoWork event handler of X calls a method Y of my controller. This method creates the WebRequest (async.) instance and the callback using AsyncCallback.
• When the response arrives the callback method Z gets called and the content will be analyzed. It can happen that the response has an unwanted content. At that moment callback Z will throw an exception.

I want to catch this exception in my main application. I tried it in DoWork and RunWorkerCompleted but nothing can be caught from there.

Error in RunWorkerCompletedEventArgs is always null.

Answer 1

Dont know what you are doing wrong. But this works like charm.

        BackgroundWorker bw = new BackgroundWorker();
        bw.DoWork += (o, s) => { throw new Exception("myMessage"); };
        bw.RunWorkerCompleted += (o, s) => { Console.WriteLine(s.Error.Message); };
        bw.RunWorkerAsync();
        Console.ReadKey(true);

So this means that somewhere your exception must be getting caught, and thus is prevented from propagating to the BWWorkCompletedEventArgs