• Any idea how to correctly use of SetParent() to make a window of my process a child window of another process?

    What I am trying to achieve is make a HUD application for poker. So my app has to display user stats on top of the poker app window.

    What I do is:

    fhWnd = FindWindow(_T("Notepad"), NULL);
     hWnd = CreateWindowEx(WS_EX_TOPMOST , _T("test"), _T("test"),
            20, 20, 400, 400, NULL, NULL, hInst, NULL);
     SetParent(hWnd, fhWnd);
     DWORD style = GetWindowLong(hWnd, GWL_STYLE);
     style = style & ~(WS_POPUP);
     SetWindowLong(hWnd, GWL_STYLE, style);
     SetWindowLong(fhWnd, GWL_STYLE, GetWindowLong(fhWnd, GWL_STYLE) | WS_CLIPCHILDREN);

    However in order to see what I drawn in my window I have to move the parent window out of the screen and back in again.

    Any ideas how to do this right?

    • Edited by Stav_9 Wednesday, December 26, 2012 6:20 AM
    Wednesday, December 26, 2012 6:10 AM


  • Hello Stav_9,

    Welcome to MSDN forum.

    According to your description, the child window did not repaint (because the child window area is not refreshed). When you move the child window, a WM_PAINT message is sent to the window and it will be repainted. Any change of the window's client area(resizing, moving) will trigger a WM_PAINT message.

    To refresh the window's update region, you can use InvalidateRect function or InvalidateRgn. They can indirectly generate WM_PAINT messages for a window by marking all or part of a client area as invalid (that must be redrawn).

    You can refer to: Invalidating the Client Area


    Damon Zheng
    MSDN Community Support | Feedback to us
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    Thursday, December 27, 2012 10:51 AM