
Declaramos :
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
Const WM_USER = &H400
Public Const CB_LIMITTEXT = &H141
Y en el load del formulario (para limitar el texto a tres caracteres) :
dim res as long
res = SendMessage(Combo1.hwnd, CB_LIMITTEXT, 3, 0)

