Dispatch.Invoke( new Action...) with a parameter

Question

Previously I had

Dispatcher.Invoke(new Action(() => colorManager.Update()));

to update display to WPF from another thread. Due to design, I had to alter the program, and I must pass ColorImageFrame parameter into my ColorStreamManager.Update() method.

Following this link, I modified my dispatcher to:

Dispatcher.Invoke(new Action<ColorStreamManager, ColorImageFrame>((p,v) => p.Update(v)));

It compiles fine but would not run at all. VS2010 says "Parameter count mismatch." In my ColorStreamManager.Update() method I have RaisePropertyChanged(() => Bitmap);

Could someone point out where did I go wrong?

The signature of ColorStreamManager.Update() method is the following:

 public void Update(ColorImageFrame frame);

Answer 1

You don't want the action to have parameters, because the Dispatcher isn't going to know what to pass to the method. Instead what you can do is close over the variable:

ColorImageFrame someFrame = ...;
Dispatcher.Invoke(new Action(() => colorManager.Update(someFrame)));

Answer 2

If you call Invoke with an Action<T1, T2> delegate, you need to pass the two Action parameters to the Invoke call:

ColorStreamManager colorManager = ...
ColorImageFrame frame = ...

Dispatcher.Invoke(
    new Action<ColorStreamManager, ColorImageFrame>((p,v) => p.Update(v)),
    colorManager,
    frame);

The Invoke overload you're using here is Dispatcher.Invoke(Delegate, Object[]).