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    public class Win32APICall
    {
        [DllImport("gdi32.dll", EntryPoint = "DeleteDC")]
        public static extern IntPtr DeleteDC(IntPtr hdc);

        [DllImport("gdi32.dll", EntryPoint = "DeleteObject")]
        public static extern IntPtr DeleteObject(IntPtr hObject);

        [DllImport("gdi32.dll", EntryPoint = "BitBlt")]
        public static extern bool BitBlt(IntPtr hdcDest, int nXDest,
            int nYDest, int nWidth, int nHeight, IntPtr hdcSrc,
            int nXSrc, int nYSrc, int dwRop);

        [DllImport("gdi32.dll", EntryPoint = "CreateCompatibleBitmap")]
        public static extern IntPtr CreateCompatibleBitmap(IntPtr hdc,
            int nWidth, int nHeight);

        [DllImport("gdi32.dll", EntryPoint = "CreateCompatibleDC")]
        public static extern IntPtr CreateCompatibleDC(IntPtr hdc);

        [DllImport("gdi32.dll", EntryPoint = "SelectObject")]
        public static extern IntPtr SelectObject(IntPtr hdc, IntPtr hgdiobjBmp);

        [DllImport("user32.dll", EntryPoint = "GetDesktopWindow")]
        public static extern IntPtr GetDesktopWindow();

        [DllImport("user32.dll", EntryPoint = "GetDC")]
        public static extern IntPtr GetDC(IntPtr hWnd);

        [DllImport("user32.dll", EntryPoint = "GetSystemMetrics")]
        public static extern int GetSystemMetrics(int nIndex);

        [DllImport("user32.dll", EntryPoint = "ReleaseDC")]
        public static extern IntPtr ReleaseDC(IntPtr hWnd, IntPtr hDC);

        public static Bitmap GetDesktop()
        {
            int screenX;
            int screenY;
            IntPtr hBmp;
            IntPtr hdcScreen = GetDC(GetDesktopWindow());
            IntPtr hdcCompatible = CreateCompatibleDC(hdcScreen);

            screenX = GetSystemMetrics(0);
            screenY = GetSystemMetrics(1);
            hBmp = CreateCompatibleBitmap(hdcScreen, screenX, screenY);

            if (hBmp != IntPtr.Zero)
            {
                IntPtr hOldBmp = (IntPtr)SelectObject(hdcCompatible, hBmp);
                BitBlt(hdcCompatible, 0, 0, screenX, screenY, hdcScreen, 0, 0, 13369376);

                SelectObject(hdcCompatible, hOldBmp);
                DeleteDC(hdcCompatible);
                ReleaseDC(GetDesktopWindow(), hdcScreen);

                Bitmap bmp = System.Drawing.Image.FromHbitmap(hBmp);

                DeleteObject(hBmp);
                GC.Collect();

                return bmp;
            }

            return null;
        }
    }