C# - Compact Framework Windows CE - GUI Thread Blocks Higher Priority Threads

I am having an issue where I have a Windows CE compact framework Application written in C#, where I have the primary GUI thread set to normal priority and a communication thread set to above normal priority to get as close to pseudo real time performance. The issue I am having is within a button handler I run a loop to load config data from a file to the GUI before allowing it to be edited. This takes around 2-3 seconds to complete. While this blocking in the event handler is happening, my higher priority communication thread is being blocked. There are no locks are thread syncs in place. The communicatio thread has no dependencies on the GUI thread.

This is how I spawn my comm thread:

        MbWorkerThread = new Thread(MbPollingThread);
        MbWorkerThread.IsBackground = true;
        MbWorkerThread.Priority = ThreadPriority.AboveNormal;
        MbWorkerThread.Start();

It is an MTA application. Also, I have tried to use Thread.Sleep(1) in the GUI event handler to yield to the higher priority threa开发者_如何学God and it does not work. I also tried using signals to yield to the higher priority thread, and that does not work. The only thing that works is if I place Application.DoEvents() in the loop while loading config in the event handler. This of coarse whas just a test, as I do not want to sprinkle Application.DoEvents() throught my code to make it work since I know Application.DoEvents() is dangerous.

My understanding is that the primary GUI thread is a foreground thread, but a thread none the less. Also, I have made the communication thread a background thread just to allow it to be killed when the primary thread is exited.

I have tried everything, I have search the Internet endlessly before asking this question.

Any help will be greatly appreciated.

P.S. - I though about a form timer but I know it runs in the GUI thread so that would not help. I though about another thread but I really did not what to marshall GUI updates via Invoke.

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Your program starts in Main(), where you typically call Application.Run( new MyForm() ). Application.Run() implements the standard Windows Message Pump, which deals with messages from the OS and other applications, including user input, inter-process communication, repaint requests, etc.

GUI events, like Button click, are dispatched via this thread. If you perform long-running work in an event handler, other messages are not being processed.

Application.DoEvents() blocks the calling thread, and waits for all pending messages to be processed. If DoEvents helps your communication thread when Sleep(1) did not, then I suspect there is a dependency between your communication thread and the GUI/Message Pump thread.

Even if this is not the case, it is not a good idea to block the GUI thread. Move your file loading into the background with ThreadPool.QueueUserWorkItem() and marshal the results back to the UI at the end with Invoke or BeginInvoke.

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BeginInvoke instead of Invoke fixed the issue. Thanks for the replies.