Window Size?

I have a problem getting my forms size. Do anyone have any houghts about how to get the size.

VB Code:

Public Declare Function GetWindowRect Lib "user32" Alias "GetWindowRect" (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
 
Dim R As RECT
GetWindowRect Me.hWnd, R
Width = R.Right - R.Left
Height = R.Bottom - R.Top

thanks :)