'API Deklarieren
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal _
  hWnd As Long, _
  ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
 
'API aufrufen
SendMessage(cmb.hWnd, CB_GETDROPPEDSTATE, 0, 0)