The main difference between the Dispatcher and other threading methods is that the Dispatcher is not actually multi-threaded. The Dispatcher governs the controls, which need a single thread to function properly; the BeginInvoke method of the Dispatcher queues events for later execution (depending on priority etc.), but still on the same thread. BackgroundWorker on the … Read more
You can grab the UI Dispatcher from the static application instance: Application.Current.Dispatcher You may want to check Application.Current for null first, as it can be cleared during a shutdown sequence.
For the thread that you’re trying to start the GUI element in, you need to set the apartment state of the thread to STA BEFORE you start it. Example: myThread.SetApartmentState(ApartmentState.STA); myThread.Start();
When you use Dispatcher.BeginInvoke it means that it schedules the given action for execution in the UI thread at a later point in time, and then returns control to allow the current thread to continue executing. Invoke blocks the caller until the scheduled action finishes. When you use BeginInvoke your loop is going to run … Read more
This is the preferred way: Windows.ApplicationModel.Core.CoreApplication.MainView.CoreWindow.Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () => { // Your UI update code goes here! }); The advantage this has is that it gets the main CoreApplicationView and so is always available. More details here. There are two alternatives which you could use. First alternative Windows.ApplicationModel.Core.CoreApplication.GetCurrentView().CoreWindow.Dispatcher This gets the active view for the app, … Read more
I’ve used volatile where I’m not sure it is necessary. Let me be very clear on this point: If you are not 100% clear on what volatile means in C# then do not use it. It is a sharp tool that is meant to be used by experts only. If you cannot describe what all … Read more
Use Dispatcher.Invoke Method. Executes the specified delegate synchronously on the thread the Dispatcher is associated with. Also In WPF, only the thread that created a DispatcherObject may access that object. For example, a background thread that is spun off from the main UI thread cannot update the contents of a Button that was created on … Read more
The problem is that you aren’t providing the exact type of delegate you want to invoke. Dispatcher.Invoke just takes a Delegate. Is it an Action<T>? If so, what is T? Is it a MethodInvoker? Action? What? If your delegate takes no arguments and returns nothing, you can use Action or MethodInvoker. Try this: _uiDispatcher.Invoke(new Action(() … Read more
I have abstracted the Dispatcher using an interface IContext: public interface IContext { bool IsSynchronized { get; } void Invoke(Action action); void BeginInvoke(Action action); } This has the advantage that you can unit-test your ViewModels more easily. I inject the interface into my ViewModels using the MEF (Managed Extensibility Framework). Another possibility would be a … Read more
Your app has a main UI thread (usually ManagedThreadId==1). Typically in a chat app your events will come in on other threads (either dedicated socket listen threads or thread pool threads from listening code). If you want to update the UI from an event that gets pull on some other thread you must use the … Read more