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'Get the test project with the "Test this code" link 'Put this section on a form with 2 command buttons Private Sub Command1_Click() Dim hInst As Long Dim Thread As Long 'Set up the CBT hook hInst = GetWindowLong(Me.hwnd, GWL_HINSTANCE) Thread = GetCurrentThreadId() hHook = SetWindowsHookEx(WH_CBT, AddressOf WinProc1, hInst, _ Thread) 'Display the message box MsgBox "This message box has been positioned at (0,0)." & _ vbCrLf & vbCrLf & "Form1 hWnd = " & Form1.hwnd End Sub Private Sub Command2_Click() Dim hInst As Long Dim Thread As Long 'Set up the CBT hook hInst = GetWindowLong(Me.hwnd, GWL_HINSTANCE) Thread = GetCurrentThreadId() hHook = SetWindowsHookEx(WH_CBT, AddressOf WinProc2, hInst, _ Thread) 'Display the message box MsgBox "This message box is centered over Form1." & _ vbCrLf & vbCrLf & "Form1 hWnd = " & Form1.hwnd End Sub 'Put this section in a module Type RECT Left As Long Top As Long Right As Long Bottom As Long End Type Public Declare Function UnhookWindowsHookEx Lib "user32" ( _ ByVal hHook As Long) As Long Public Declare Function GetWindowLong Lib "user32" Alias _ "GetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long) _ As Long Public Declare Function GetCurrentThreadId Lib "kernel32" () As Long Public Declare Function SetWindowsHookEx Lib "user32" Alias _ "SetWindowsHookExA" (ByVal idHook As Long, ByVal lpfn As Long, _ ByVal hmod As Long, ByVal dwThreadId As Long) As Long Public Declare Function SetWindowPos Lib "user32" ( _ ByVal hwnd As Long, ByVal hWndInsertAfter As Long, _ ByVal x As Long, ByVal y As Long, ByVal cx As Long, _ ByVal cy As Long, ByVal wFlags As Long) As Long Public Declare Function GetWindowRect Lib "user32" (ByVal hwnd _ As Long, lpRect As RECT) As Long Public Const GWL_HINSTANCE = (-6) Public Const SWP_NOSIZE = &H1 Public Const SWP_NOZORDER = &H4 Public Const SWP_NOACTIVATE = &H10 Public Const HCBT_ACTIVATE = 5 Public Const WH_CBT = 5 Public hHook As Long Public Function WinProc1(ByVal lMsg As Long, ByVal wParam As Long, _ ByVal lParam As Long) As Long If lMsg = HCBT_ACTIVATE Then 'Show the MsgBox at a fixed location (0,0) SetWindowPos wParam, 0, 0, 0, 0, 0, _ SWP_NOSIZE Or SWP_NOZORDER Or SWP_NOACTIVATE 'Release the CBT hook UnhookWindowsHookEx hHook End If WinProc1 = False End Function Public Function WinProc2(ByVal lMsg As Long, ByVal wParam As Long, _ ByVal lParam As Long) As Long Dim rectForm As RECT, rectMsg As RECT Dim x As Long, y As Long 'On HCBT_ACTIVATE, show the MsgBox centered over Form1 If lMsg = HCBT_ACTIVATE Then 'Get the coordinates of the form and the message box so that 'you can determine where the center of the form is located GetWindowRect Form1.hwnd, rectForm GetWindowRect wParam, rectMsg x = (rectForm.Left + (rectForm.Right - rectForm.Left) / 2) - _ ((rectMsg.Right - rectMsg.Left) / 2) y = (rectForm.Top + (rectForm.Bottom - rectForm.Top) / 2) - _ ((rectMsg.Bottom - rectMsg.Top) / 2) 'Position the msgbox SetWindowPos wParam, 0, x, y, 0, 0, _ SWP_NOSIZE Or SWP_NOZORDER Or SWP_NOACTIVATE 'Release the CBT hook UnhookWindowsHookEx hHook End If WinProc2 = False End Function

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