positionMsgboxHook.vb

Private Declare PtrSafe Function GetCurrentThreadId Lib "kernel32" _
    () As Long
Private Declare PtrSafe Function SetWindowsHookEx Lib "user32" Alias "SetWindowsHookExA" _
    (ByVal idHook As Long, ByVal lpfn As LongPtr, ByVal hmod As LongPtr, ByVal dwThreadId As Long) As LongPtr

Private Declare PtrSafe Function SetDlgItemText Lib "user32" Alias "SetDlgItemTextA" _
    (ByVal hDlg As LongPtr, ByVal nIDDlgItem As Long, ByVal lpString As String) As Long

Private Declare PtrSafe Function CallNextHookEx Lib "user32" _
    (ByVal hHook As LongPtr, ByVal ncode As Long, ByVal wParam As LongPtr, lParam As Any) As LongPtr

Private Declare PtrSafe Function UnhookWindowsHookEx Lib "user32" _
    (ByVal hHook As LongPtr) As Long
Private Declare PtrSafe Sub CopyMemory Lib "kernel32" _
    Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As LongPtr)

Private Declare PtrSafe Function GetWindowText Lib "user32" _
    Alias "GetWindowTextA" (ByVal hwnd As Long, ByVal lpString As String, ByVal cch As Long) As Long

Public Declare PtrSafe Function GetWindowTextLength Lib "user32" _
    Alias "GetWindowTextLengthA" (ByVal hwnd As Long) As Long

Public Declare PtrSafe 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

Private hHook As LongPtr
    
Private Const WH_CBT = 5            ' hook type
Private Const HCBT_ACTIVATE = 5     ' activate window
Private Const IDYES = 6
Private Const HCBT_MOVESIZE = 0
Private Const SWP_NOSIZE = &H1
Private Const SWP_NOACTIVATE = &H10

Type RECT
    Left As Long
    Top As Long
    Right As Long
    Bottom As Long
End Type

Private Function MsgBoxCustom_Proc(ByVal lMsg As Long, ByVal wParam As Long, ByVal lParam As LongPtr) As LongPtr
  
    Dim title As String
    title = getNameFromHwnd(wParam)
    
    If lMsg = HCBT_ACTIVATE And title = "Hellow" Then
        Debug.Print "activated"
        SetWindowPos wParam, 0, 10, 10, 200, 200, SWP_NOSIZE Or SWP_NOACTIVATE
    End If
    
    MsgBoxCustom_Proc = CallNextHookEx(hHook, lMsg, wParam, lParam)
End Function

Public Sub addHook()

    hHook = SetWindowsHookEx(WH_CBT, AddressOf MsgBoxCustom_Proc, 0, GetCurrentThreadId)
    
    MsgBox "test", vbSystemModal, "Hellow"
    
    If hHook <> 0 Then UnhookWindowsHookEx hHook ' this is very important
End Sub

Public Function getNameFromHwnd(hwnd As Long) As String
    Dim title As String * 255
    Dim tLen As Long
    tLen = GetWindowTextLength(hwnd)
    GetWindowText hwnd, title, 255
    getNameFromHwnd = Left(title, tLen)
End Function