Winforms WPF Interop - Wpf控件呈现为非活动状态

Question

I have a similar problem to this question regarding painting of wpf controls

The application I work on is a rather large Windows forms threaded application with several wpf user controls throughout the application. The problem occurs in a plugin of the application where a third party c++ library is called on a separate thread, WndProc is overriden to get the progress updates from the third party library. I have yet to determine the exact scenario that causes the problem but similar to the above mentioned question, after a few runs the wpf controls fails to paint and update.

Setting the width of the elementhosts does solve the painting issue for most of the controls but after this all the wpf controls in the application seems to become 'unresponsive' - visually... the progress bars fails to show progress (though the value does change), scrollbars does not respond, selecting an item in the listview does not highlight it(it does get highlighted after resizing and it does actually get selected - you just can see it is selected) the treeviews does not paint after the resizing, it only shows a black background where the treeview should be (though when I click on the items where they should be in the treeview, the events does get trigerred)

I know I should probably find out the root of the problems that causes this first (its hapening rather randomely and is hard to trap) - allthough putting a breakpoint in the WndProc method does seem to cause it to fail on a regualar base...

What I was hoping for is a way to 'reactivate'/refresh all the other controls throughout the application... I am an intermediate wpf, c# developer and dont really know enough yet about the messaging and events that happens in the background to use them effectively ... my thought is that some event or message that tells wpf to redraw must be broken or interrupted or something - how can I determine what is broken and maybe reactivate it??

Any advice will be much appreciated...

Thank You

Answer 1

It could be that the event that causes the WPF control graph render is never being processed because of that WndProc override.

Since you are inter-oping with WinForms, you can force the events to process by performing a call to Application.DoEvents(); somewhere. Perhaps after you update the progress bar.