Public Declare Function GetWindowRect Lib "user32" (ByVal hwnd As Long, lpRect As RECT) As Long
Public Type RECT
  Left As Long
  Top As Long
  Right As Long
  Bottom As Long
End Type
Public Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Public Const CB_GETITEMHEIGHT = &H154
Public Const SWP_NOMOVE = &H2
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 Sub ReSizeCombo2(cbo As Control, n As Integer)

  Dim cboLeft As Long, cboTop As Long, cboWidth As Long
  Dim cboHeight As Long, h As Long, re As RECT
  Call GetWindowRect(cbo.hwnd, re)
  cboLeft = re.Left
  cboTop = re.Top
  cboWidth = re.Right - re.Left
  h = SendMessage(cbo.hwnd, CB_GETITEMHEIGHT,  0 ,  0 )
  cboHeight = h * (n +  2 )
  SetWindowPos cbo.hwnd,  0 , cboLeft, cboTop, cboWidth, cboHeight, SWP_NOMOVE

End Sub

ReSizeCombo2 Me.MyCombobox,  20