[DllImport("user32.dll")]
static extern int GetWindowRgn(IntPtr hWnd, IntPtr hRgn);
//Region Flags - The return value specifies the type of the region that the function obtains. It can be one of the following values.
const int ERROR = 0;
const int NULLREGION = 1;
const int SIMPLEREGION = 2;
const int COMPLEXREGION = 3;
VB.NET Signature:
<DllImport("user32.dll")> _
Private Shared Function GetWindowRgn(ByVal hWnd As IntPtr, ByVal hRgn As IntPtr) As Integer
End Function