For UWP apps, I believe you're going to have to use the Bluetooth GATT[^] classes. System.Net.EndPoint isn't present in UWP. This space for rent

thanks, this works private void DrawEventHandler(object sender, DrawHandler.DrawEventArgs e) { this.Invalidate(); }

thanks, I'm using the text boxes instead of labels.

very helpful, Thank you

Thanks for the ideas, I'll see how this works out Ron

That's a different situation though, that's a 'make this method self-marshalling' rather than 'marshal this method call'. The StackOverflowEx is pretty obvious if you don't guard this. If you put the responsibility on the caller (i.e. they must use control.Invoke(() => control.SomeFunction())), or you provide an explicit SomeFunctionAsync (using BeginInvoke) then it's not an issue. On a different note you don't need to define a void delegate type, MethodInvoker exists for this already.