Screenshot method generates black images

Question

After failing to use the control.drawtobitmap in c#, my second option was to take screenshots of the desktop and crop out the desired sections. My hiccup shows up once i sw

Answer 1

Finally this code seems to work even when i have switched users.

Code to take screen shot of any unsaved Notepad process ("Untitled - Notepad")

    private void Form1_Load(object sender, EventArgs e)
    {
        //loop for debugging
        int c = 0;
        while(true)
        {
            c++;
            System.Drawing.Bitmap image = CaptureWindow(FindWindow(null, "Untitled - Notepad"));
            image.Save(".\\picture"+c.ToString()+".jpg");
            Thread.Sleep(5000);
        }

    }

    [DllImport("user32.dll")]
    public static extern bool PrintWindow(IntPtr hwnd, IntPtr hdcBlt, uint nFlags);
    [DllImport("user32.dll")]
    public static extern IntPtr GetWindowDC(IntPtr hWnd);
    [DllImport("user32.dll", SetLastError = true)]
    static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

    public System.Drawing.Bitmap CaptureWindow(IntPtr hWnd)
    {
        System.Drawing.Rectangle rctForm = System.Drawing.Rectangle.Empty;
        using (System.Drawing.Graphics grfx = System.Drawing.Graphics.FromHdc(GetWindowDC(hWnd)))
        {
            rctForm = System.Drawing.Rectangle.Round(grfx.VisibleClipBounds);
        }
        System.Drawing.Bitmap pImage = new System.Drawing.Bitmap(rctForm.Width, rctForm.Height);
        System.Drawing.Graphics graphics = System.Drawing.Graphics.FromImage(pImage);
        IntPtr hDC = graphics.GetHdc();

        try
        {
            PrintWindow(hWnd, hDC, (uint)0);
        }
        finally
        {
            graphics.ReleaseHdc(hDC);
        }
        return pImage;
    }

Note that the window may be hidden but it must still be maximized on the user account to get a complete screen shot.