private static extern bool AdjustWindowRectEx(ref Win32Rectangle lpRect, WindowStyle dwStyle, bool bMenu, ExtendedWindowStyle dwExStyle);
public static Rectangle AdjustWindowRectEx(int width, int height, WindowStyle style, bool menu, ExtendedWindowStyle extendedStyle)
{
var rect = new Win32Rectangle
{
Right = width,
Bottom = height
};
AdjustWindowRectEx(ref rect, style, menu, extendedStyle);
return rect.ToRectangle();
}