WPF TextBox not accepting Input when in ElementHost in Window Forms

Question

We are developing a UI Control in WPF to be consumed within an existing Windows Forms / MFC application engine (Rhino 3D).

The application engine exposes the ability

Answer 1

I have a similar issue with a wxWidgets parent window and embedded WPF TextBox controls. I found that although attaching ChildHwndSourceHook does solve the problem of not receiving keyboard input, I ended up with occasional duplicate space characters. It seems the WM_KEYDOWN message handles the space characters reliably, but a duplicate WM_CHAR message is also received for some of the spaces. To solve this I added the following clause to the body of the ChildHwndSourceHook function, which simply ignores the WM_CHAR space character:

        const UInt32 WM_CHAR = 0x0102;

        if (msg == WM_CHAR)
        {
            // avoid duplicated spaces when parent window is a native window
            if (wParam.ToInt32() == 32)
                handled = true;
        }