C#屏幕截图类

[Visual Stdio 2005下调试通过]

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    /// <summary>
    /// 提供全屏和指定窗口的截图 以及保存为文件的类
    /// </summary>
    public class ScreenCapture
    {
        /// <summary>
        /// 全屏截图
        /// </summary>
        /// <returns></returns>
        public Image CaptureScreen()
        {
            return CaptureWindow( User32.GetDesktopWindow() );
        }
        /// <summary>
        /// 指定窗口截图
        /// </summary>
        /// <param name="handle">窗口句柄. (在windows应用程序中, 从Handle属性获得)</param>
        /// <returns></returns>
        public Image CaptureWindow(IntPtr handle)
        {
            IntPtr hdcSrc = User32.GetWindowDC(handle);
            User32.RECT windowRect = new User32.RECT();
            User32.GetWindowRect(handle,ref windowRect);
            int width = windowRect.right - windowRect.left;
            int height = windowRect.bottom - windowRect.top;
            IntPtr hdcDest = GDI32.CreateCompatibleDC(hdcSrc);
            IntPtr hBitmap = GDI32.CreateCompatibleBitmap(hdcSrc,width,height);
            IntPtr hOld = GDI32.SelectObject(hdcDest,hBitmap);
            GDI32.BitBlt(hdcDest,0,0,width,height,hdcSrc,0,0,GDI32.SRCCOPY);
            GDI32.SelectObject(hdcDest,hOld);
            GDI32.DeleteDC(hdcDest);
            User32.ReleaseDC(handle,hdcSrc);
            Image img = Image.FromHbitmap(hBitmap);
            GDI32.DeleteObject(hBitmap);
            return img;
        }
        /// <summary>
        /// 指定窗口截图 保存为图片文件
        /// </summary>
        /// <param name="handle"></param>
        /// <param name="filename"></param>
        /// <param name="format"></param>
        public void CaptureWindowToFile(IntPtr handle, string filename, ImageFormat format)
        {
            Image img = CaptureWindow(handle);
            img.Save(filename,format);
        }
        /// <summary>
        /// 全屏截图 保存为文件
        /// </summary>
        /// <param name="filename"></param>
        /// <param name="format"></param>
        public void CaptureScreenToFile(string filename, ImageFormat format)
        {
            Image img = CaptureScreen();
            img.Save(filename,format);
        }
    
        /// <summary>
        /// 辅助类 定义 Gdi32 API 函数
        /// </summary>
        private class GDI32
        {
          
            public const int SRCCOPY = 0x00CC0020;
            [DllImport("gdi32.dll")]
            public static extern bool BitBlt(IntPtr hObject,int nXDest,int nYDest,
                int nWidth,int nHeight,IntPtr hObjectSource,
                int nXSrc,int nYSrc,int dwRop);
            [DllImport("gdi32.dll")]
            public static extern IntPtr CreateCompatibleBitmap(IntPtr hDC,int nWidth,
                int nHeight);
            [DllImport("gdi32.dll")]
            public static extern IntPtr CreateCompatibleDC(IntPtr hDC);
            [DllImport("gdi32.dll")]
            public static extern bool DeleteDC(IntPtr hDC);
            [DllImport("gdi32.dll")]
            public static extern bool DeleteObject(IntPtr hObject);
            [DllImport("gdi32.dll")]
            public static extern IntPtr SelectObject(IntPtr hDC,IntPtr hObject);
        }

        /// <summary>
        /// 辅助类 定义User32 API函数
        /// </summary>
        private class User32
        {
            [StructLayout(LayoutKind.Sequential)]
            public struct RECT
            {
                public int left;
                public int top;
                public int right;
                public int bottom;
            }
            [DllImport("user32.dll")]
            public static extern IntPtr GetDesktopWindow();
            [DllImport("user32.dll")]
            public static extern IntPtr GetWindowDC(IntPtr hWnd);
            [DllImport("user32.dll")]
            public static extern IntPtr ReleaseDC(IntPtr hWnd,IntPtr hDC);
            [DllImport("user32.dll")]
            public static extern IntPtr GetWindowRect(IntPtr hWnd,ref RECT rect);
        }
    }