Why do I get a height and Width of 0?

Why do I get a heigh and Width of 0 with the below:

    static void Main(string[] args)
    {
        Process notePad = new Process();
        notePad.StartInfo.FileName = "notepad.exe";
        notePad.Start();
        IntPtr handle = notePad.Handle;

        RECT windowRect = new RECT();
        GetWindowRect(handle, ref windowRect);
        int width = windowRect.Right - windowRect.Left;
        int height = windowRect.Bottom - windowRect.Top;

        Console.WriteLine("Height: " + height + ", Width: " 开发者_JAVA技巧+ width);
        Console.ReadLine();
    }

Here is my definition of GetWindowRect:

    [DllImport("user32.dll")]
    [return: MarshalAs(UnmanagedType.Bool)]
    static extern bool GetWindowRect(IntPtr hWnd, ref RECT lpRect);

This is my definition for RECT:

    [StructLayout(LayoutKind.Sequential)]
    public struct RECT
    {
        public int Left;        // x position of upper-left corner
        public int Top;         // y position of upper-left corner
        public int Right;       // x position of lower-right corner
        public int Bottom;      // y position of lower-right corner
    }

Thanks all for any help.

You are passing a process handle to a function, GetWindowRect, that expects a window handle. Naturally, this fails. You should send Notepad.MainWindowHandle instead.

You may be querying the size before notepad has fully started up. Try this:

    notePad.Start();
    notePad.WaitForInputIdle(); // Waits for notepad to finish startup
    IntPtr handle = notePad.Handle;

I like using pinvoke.net to sanity check all my PInvokes. GetWindowRect is described well at: http://pinvoke.net/default.aspx/user32/GetWindowRect.html