CODEWITHSUNDEEP
wpfmultithreading.net-4.0processdispatcher
Dave
Dave

Reputation: 15016

Displaying a WPF dialog from the main thread in a .NET library

I've read several posts here and via references from google, but haven't come up with the proper solution.

I have an assembly that displays a dialog, but that dialog needs to be shown from the main thread. The caller could be a .NET application or native application.

Conceptually, it seems like I simply need to get the application's main thread ID, and then call System.Windows.Threading.Dispatcher.FromThread( main_thread_id_here) to get the Dispatcher, and then call Invoke to display my dialog from the main thread. However, I haven't been able to figure out how to get the main thread ID.

My next approach was to (following advice from another SO question) iterate over Process.GetCurrentProcess().Threads, and get the thread ID of the ProcessThread that was started first. But now that I have this ProcessThread, I don't have a way to get the corresponding Thread object. I figured that I could next get a list of all running .NET threads in the current process, and compare their thread IDs via GetHashCode to determine which one is the main thread. I could then use FromThread to get the Dispatcher... but I haven't been able to find any information on retrieving anything but ProcessThreads!

Does anyone have tips on how to solve this problem using either approach I have explained above, or maybe another approach? Please keep in mind that I don't have control over the calling application.

Upvotes: 1

Views: 2956

Answers (1)

RandomEngy
RandomEngy

Reputation: 15413

Application.Current.Dispatcher.BeginInvoke(new Action(() =>
{
    // Show dialog
}));

You could also grab the dispatcher from the Window.Dispatcher property.

Upvotes: 2

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