Question

We have a silverlight application which uses a dispatcher and I would appreciate any help explaining what the following codes does? (unfortunately the developer who wrote the code has left).

So what we have is the following:

public class ABC
{
    private Dispatcher dispatcher;
    private Thread threadRunner;

    public void ABC()
    {
       threadRunner= new Thread(ThreadRunnerMethod)
                         {
                           IsBackground = true, 
                           ApartmentState = ApartmentState.STA
                         };
       threadRunner.Start();
    }

    private static void ThreadRunnerMethod()
    {
       Dispatcher.Run();
    }


    public void MainMethod()
    {
       dispatcher = Dispatcher.FromThread(threadRunner);
       dispatcher.Invoke(new Action(() => 
                                     // "DO SOME WORK WITH A COM OBJECT"
                                      ));

    }
}

I have some basic experience with threading but I have no idea how this all works?

JD

Answer 1

It’s the equivalent of Control.Invoke in Windows Forms, basically – it’s just been separated into its own object.

As I understand it, Dispatcher.Run will basically start an event loop, and you can marshall calls into that event loop using Dispatcher.Invoke. Dispatcher.FromThread finds the Dispatcher object which is responsible for a given thread – so in this case, it finds the event loop running in the new thread.

So in your code, the delegate created with the lambda expression will execute in the newly created thread.