WPF/Multithreading: UI Dispatcher in MVVM

Question

So say in an MVVM environment, I'm in a background thread and I'd like to run an update on a ui control. So normally I'd go myButton.Dispatcher.BeginInvoke(blabla) but I don't have access to myButton (because the viewmodel doesn't have access to the view's controls). So what is the normal pattern for doing this?

(I guess there's always binding, but I'd like to know how to do it via the dispatcher)

Answer 1

I usually use Application.Current.Dispatcher: since Application.Current is static, you don't need a reference to a control

Answer 2

From Caliburn Micro source code :

public static class Execute
{
    private static Action<System.Action> executor = action => action();

    /// <summary>
    /// Initializes the framework using the current dispatcher.
    /// </summary>
    public static void InitializeWithDispatcher()
    {
#if SILVERLIGHT
        var dispatcher = Deployment.Current.Dispatcher;
#else
        var dispatcher = Dispatcher.CurrentDispatcher;
#endif
        executor = action =>{
            if(dispatcher.CheckAccess())
                action();
            else dispatcher.BeginInvoke(action);
        };
    }

    /// <summary>
    /// Executes the action on the UI thread.
    /// </summary>
    /// <param name="action">The action to execute.</param>
    public static void OnUIThread(this System.Action action)
    {
        executor(action);
    }
}

Before using it you'll have to call Execute.InitializeWithDispatcher() from the UI thread then you can use it like this Execute.OnUIThread(()=>SomeMethod())