My application has several independent "top-level" windows, which all have completely different functions/workflows.
I am currently using ShowDialog() to make a WPF Window modal. The modal window is a child of one of the main windows. However, it is blocking all the top-level windows once it is open. I would like the dialog to block ONLY the parent window it was launched from. Is this possible?
I'm not sure if it matters, but the window that opens the dialog is the initial window of the app–so all other top-level windows are opened from it.
Best Answer
I had the same problem and implemented the modal dialog behavior as described in this post: http://social.msdn.microsoft.com/Forums/vstudio/en-US/820bf10f-3eaf-43a8-b5ef-b83b2394342c/windowsshowmodal-to-parentowner-window-only-not-entire-application?forum=wpf
I also tried a multiple UI thread approach, but this caused problems with third-party libraries (caliburn micro & telerik wpf controls), since they are not built to be used in multiple UI threads. It is possible to make them work with multiple UI threads, but I prefer a simpler solution...
If you implement the dialog as described, you can not use the DialogResult property anymore, since it would cause a "DialogResult can be set only after Window is created and shown as dialog" exception. Just implement your own property and use it instead.
You need the following windows API reference:
Then use this:
This is the event handler which re-enables the parent window, when the dialog is closed:
And this is the ShowAndWaitHelper needed to achieve the modal dialog behavior (this blocks the execution of the thread, but still executes the message loop.