WPF/Multithreading: UI Dispatcher in MVVM

I tend to have my ViewModels inherit from DependencyObject and ensure that they are constructed on the UI thread, which poises them perfectly to handle this situation - they have a Dispatcher property that corresponds to the UI thread's dispatcher. Then, you don't need to pollute your view with the ViewModel's implementation details.

Some other pluses:

• Unit testability: you can unit test these without a running application (rather than relying on Application.Current.Dispatcher)
• Loose coupling between View & ViewModel
• You can define dependency properties on your ViewModel and write no code to update the view as those properties change.

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

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())