Keep A Window in Focus (SetFocus)
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  1. #1
    Join Date
    May 2005
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    Keep A Window in Focus (SetFocus)

    I know that you can give a window focus by using the SetFocus function.

    But what if you want to give the window focus, AND PREVENT other windows from reclaiming that focus until you are ready to relinquish focus. Is there any way to do this?

    Thanks,
    Johnny

  2. #2
    Join Date
    May 2005
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    5

    Re: Keep A Window in Focus (SetFocus)

    anyone?

  3. #3
    Join Date
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    Re: Keep A Window in Focus (SetFocus)

    THE METHOD DESCRIBED IN THIS POST DOES NOT WORK AT ALL!

    This behaviour is not very nice for other applications.

    But, i can see a solution idea:
    Disable all other windows.
    For that:
    call EnumWindows and call EnableWindow(hWnd,FALSE) on each window passed to the callback except the top-level window containing the control you want to focus.
    Be sure to save the return value of EnableWindow which is non-zero if the window was already disabled.
    So when you want to relinquish the control's focus, you must call EnableWindow(hWnd,TRUE) on each window whose saved value corresponds to an already disabled window.
    To save this value, you can call the SetProp function with an improbable property name to don't interfere with existing properties.
    This property name can be a GUID appended to a human-readable value, like "EnableState5494D652-B304-49c9-BDD1-6516F179E5BA".
    Save the value ((HANDLE)1) to indicate a window that was enabled, and ((HANDLE)2) to indicate a window that was disabled.

    But, new windows could be created during the period you want to have the exclusive focus.
    In that case, you can handle windows creations with SetWindowsHookEx with idHook=WH_SHELL
    And you need to call the same procedure that you called in the EnumWindows callback on each created window ( the HSHELL_WINDOWCREATED code is sent to the ShellProc).
    Because it does not really handle window creation, but window apparitions (i mean that hidden windows that are shown are considered to be "created"), you must test for the presence of your property using GetProp, and if it returns NULL, that means that it is really a new window, and in that case, and only in that case, you must call the disabling procedure which also save the state of the window.

    There is always a problem : What to do, if the enabled state of some windows change during the period you want to have the exclusive focus ?
    For windows that must finally be enabled, there is no problem, because if they were disabled at the first time, no functions will be called on them, and if they were initially enabled, your pogram will just call EnabledWindow(hWnd,TRUE), and so will not modify their state.
    Last edited by SuperKoko; May 16th, 2005 at 09:21 AM. Reason: Focus removed when the user click on a disabled window!

  4. #4
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    Re: Keep A Window in Focus (SetFocus)

    If all you actually want is for the appication to stay on top of all others then you could try using SetWindowPos with the first parameter set to &wndTopMost

  5. #5
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    Re: Keep A Window in Focus (SetFocus)

    Excuse me JohnnyBGood, but my solution does not work at all.

    Because clicking on a disabled window does not set the focus on it, but remove the focus from the currently selected window.

    When i posted it, i was on a computer without any programming language, so i had not tested it at all.

  6. #6
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    Re: Keep A Window in Focus (SetFocus)

    I have not found any solution, but i can say what does not work:

    treating the WM_ACTIVATEAPP or WM_ACTIVATE messages by activating the window when it is deactivated does not work.
    Idem for WM_KILLFOCUS.

    The SetCapture function does not capture the mouse if the mouse button is down, so it is impossible to use it to avoid that the user click on an other window (moreover, it cannot stop the user from using the keyboard to move from one application to another).

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