static extern bool GetClientRect(IntPtr hWnd, out RECT lpRect);
/// <summary>
/// Get the size of the window
/// </summary>
/// <param name="windowHandle">Window handle of the target window</param>
/// <returns>RECT of the top, left, bottom, and right of the window</returns>
public static RECT GetWindowSize(IntPtr windowHandle)
{
if (windowHandle == IntPtr.Zero) return new RECT();
// Get the Top Left, and Bottom Right coords of the window client area
RECT result = new RECT();
GetClientRect(windowHandle, out result);
return result;
}
