Dispatcher.CurrentDispatcher vs. Application.Current.Dispatcher

.net, dispatcher, wpf

Solution

My gut tells me that Application.Current.Dispatcher will never change and is global to all threads in the current application, while Dispatcher.CurrentDispatcher may create a new instance of Dispatcher depending on the thread from which it was called.

That is correct.

Additionally, there is no point whatsoever in accessing `Dispatcher.CurrentDispatcher` from a non-UI thread. It will do nothing unless you call `Dispatcher.Run`, and going into an infinite message loop is not what you want to be doing from within worker threads.

So:

In the most common scenario, where your app only has a single UI thread, `Application.Current.Dispatcher` and `Dispatcher.CurrentDispatcher` from within the UI thread will return the same instance. Which one you use is simply a matter of preference.

If your app has more than one UI thread then each `DispatcherObject` will be permanently associated with the dispatcher of the UI thread it was created in upon construction. In this case, `Application.Current.Dispatcher` will refer to the dispatcher of the thread your application spawned with; you will not be able to use it to post messages to controls owned by your other UI threads.

Problem

Original source