Unregister Guiregistermsg Message

[greenmachine]

Is there a way to unregister a message registered by GuiRegisterMsg? I thought that it would have the format of HotKeySet if it were possible, but it doesn't appear to work like that. Should I simply re-route the msg to a dummy function when I don't want it, and route it back to the real function when I do? I just thought about that, and that may have to be the workaround, but I was still wondering if it would be possible to unregister the registered messages instead of being forced to have them registered at all times (once initially registered).

Edit - it doesn't appear that you can change the function either... once it's registered to a certain function, it doesn't move.

Edited April 11, 2006 by greenmachine

[greenmachine]

New findings. Turns out you can't actually call GuiRegisterMsg with "" as the function name (it freaks and errors out). Also, when changing the registered msg to a dummy func, it must be called twice in succession in order for it to work.

Here's the code I used to test. Thanks to LazyCat for coming up with it.

expandcollapse popup

HotKeySet ("1", "SetMSG")
HotKeySet ("2", "UnSetMSG")
Global Const $WM_WINDOWPOSCHANGING = 0x0046
Global Const $SPI_GETWORKAREA = 0x30

Global $nGap = 30, $nEdge = BitOR(1, 2, 4, 8); Left, Top, Right, Bottom

$hGUI = GUICreate("Snapped window", 300, 200)

GUISetState()

While 1
    $GUIMsg = GUIGetMsg()
    
    Switch $GUIMsg
        Case $GUI_EVENT_CLOSE
            ExitLoop
    EndSwitch
WEnd

Func SetMSG()
    $IsSet = GUIRegisterMsg($WM_WINDOWPOSCHANGING, "MY_WM_WINDOWPOSCHANGING")
    MsgBox (0, "Set Docking?", $IsSet)
EndFunc

Func UnSetMSG()
    $IsSet = GUIRegisterMsg($WM_WINDOWPOSCHANGING, "Dummy")
    MsgBox (0, "UnSet Docking?", $IsSet)
EndFunc

Func Dummy()
    TrayTip ("should be...", "in dummy", 1)
   ; dummy
EndFunc

Func MY_WM_WINDOWPOSCHANGING($hWnd, $Msg, $wParam, $lParam)
#cs
    HWND hwnd;
    HWND hwndInsertAfter;
    int x;
    int y;
    int cx;
    int cy;
    UINT flags;
#ce
    Local $stRect = DllStructCreate("int;int;int;int")
    Local $stWinPos = DllStructCreate("uint;uint;int;int;int;int;uint", $lParam)
    DllCall("User32.dll", "int", "SystemParametersInfo", "int", $SPI_GETWORKAREA, "int", 0, "ptr", DllStructGetPtr($stRect), "int", 0)
    Local $nLeft   = DllStructGetData($stRect, 1)
    Local $nTop = DllStructGetData($stRect, 2)
    Local $nRight  = DllStructGetData($stRect, 3) - DllStructGetData($stWinPos, 5)
    Local $nBottom = DllStructGetData($stRect, 4) - DllStructGetData($stWinPos, 6)
    If BitAND($nEdge, 1) and Abs($nLeft   - DllStructGetData($stWinPos, 3)) <= $nGap Then DllStructSetData($stWinPos, 3, $nLeft)
    If BitAND($nEdge, 2) and Abs($nTop  - DllStructGetData($stWinPos, 4)) <= $nGap Then DllStructSetData($stWinPos, 4, $nTop)
    If BitAND($nEdge, 4) and Abs($nRight  - DllStructGetData($stWinPos, 3)) <= $nGap Then DllStructSetData($stWinPos, 3, $nRight)
    If BitAND($nEdge, 8) and Abs($nBottom - DllStructGetData($stWinPos, 4)) <= $nGap Then DllStructSetData($stWinPos, 4, $nBottom)
    Return 0
EndFunc

When I ran it, I initially moved the window near a border - no docking. Then I pressed 1, got the MsgBox, moved it toward a border, and got docking. Then I pressed 2, got the MsgBox declaring success, moved it toward a border, and it still docked. Then I pressed 2 again, got the MsgBox declaring success again, moved it toward a border, and this time it didn't dock. Interesting....