Portable class library equivalent of Dispatcher.Invoke or Dispatcher.RunAsync

Question

In .NET, Windows 8 and Windows Phone 7 I have code similar to this:

public static void InvokeIfRequired(this Dispatcher dispatcher, Action action)
{
    if (         


        

Answer 1

With the advent of the TPL. I came up with a slightly improved version of the accepted answer which returns a task and can be await'ed using the new async and await keywords.

public Task RunAsync(Action action)
{
    TaskCompletionSource