How can I keep a WPF Image from blocking if the ImageSource references an unreachable Url?

Question

I\'m writing a WPF application and trying to bind an image to my view model with the following XAML:

Answer 1

Well I think I found out why it is happening...

I dug around with Reflector a bit to try to find out what exactly was getting called. Inside the BitmapDecoder I found a simple call to a WebRequest.BeginGetResponseStream.

I wrote a quick console app to test:

static void Main(string[] args)
{
    DateTime start = DateTime.Now;

    WebRequest request = WebRequest.Create("http://nonexistserver/myicon.jpg");
    IAsyncResult ar = request.BeginGetResponse((AsyncCallback)delegate(IAsyncResult result)
    {
        try
        {
            WebResponse response = request.EndGetResponse(result);
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
        }
    }, null);

    Console.WriteLine(DateTime.Now - start);
    ar.AsyncWaitHandle.WaitOne();

    Console.WriteLine("Done");
    Console.ReadKey();
}

Without Fiddler running, the output is 2-3 seconds. With Fiddler running, the output is ~.25 seconds.

Doing some more digging, it looks like BeginGetResponse (which is what WPF is using under the hood) blocks until name resolution is complete.

See this question: webrequest.begingetresponse is taking too much time when the url is invalid

So I understand why the blocking occurs now, but I don't know a clean solution for my application. :(