How to execute code in the GUI Thread?

Question

I have a FileSystemWatcher that react on the Changed event.

I want to open the file, read its content display it in a textbox and hide the popup that has been create

Answer 1

Just wrap extendedNotifyIcon_OnHideWindow(); into a Dispatcher.Invoke()

But I would rather do it (all im XAML) using an Animation and with an EvenTrigger that triggers upon the TimeLine.Completed event.