Private Declare Function MessageBox Lib "user32" Alias _
   "MessageBoxA" _
   (ByVal hwnd As Long, ByVal lpText As String, _
    ByVal lpCaption As String, ByVal wType As Long) As Long
 
Private Declare Function GetActiveWindow Lib "user32" () As Long
 
Private Declare Function SendDlgItemMessage Lib "USER32.DLL" Alias _
   "SendDlgItemMessageA" _
   (ByVal hDlg As Long, ByVal nIDDlgItem As Long, _
    ByVal wMsg As Long, ByVal wParam As Long, _
    ByVal lParam As String) As Long
 
Private Const WM_SETTEXT = &HC
Private Const IDCANCEL = 2
Private Const IDYES = 6
Private Const IDNO = 7
Private Const IDCLOSE = 8
Private Const IDCONTINUE = 11
 
Private Sub Command1_Click()
   Timer1.Enabled = True
   MessageBox Form1.hwnd, "Test", "Test", vbInformation Or vbApplicationModal
End Sub
 
Private Sub Form_Load()
   Timer1.Interval = 50
   Timer1.Enabled = False
End Sub
 
Private Sub Timer1_Timer()
   Dim hDlg As Long
   Dim a As String
 
   hDlg = GetActiveWindow()
 
   SendDlgItemMessage hDlg, IDCANCEL, WM_SETTEXT, 0, "KO"
 
   Timer1.Enabled = False
End Sub