C# 截取屏幕个人总结

//1 简易截图方法，不能截取透明窗体
            Bitmap screenBitmap = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height);
            Graphics g = Graphics.FromImage(screenBitmap);
            g.CopyFromScreen(0, 0, 0, 0, Screen.PrimaryScreen.Bounds.Size);
            g.Dispose();




//2 使用API截图

/// <summary>
        /// Windows API BitBlt 函数
        /// </summary>
        /// <param name="hdcDest">目标设备的句柄</param>
        /// <param name="nXDest">目标对象的左上角的X坐标</param>
        /// <param name="nYDest">目标对象的左上角的Y坐标</param>
        /// <param name="nWidth">目标对象的矩形的宽度</param>
        /// <param name="nHeight">目标对象的矩形的高度</param>
        /// <param name="hdcSrc">源设备的句柄</param>
        /// <param name="nXSrc">源对象的左上角的X坐标</param>
        /// <param name="nYSrc">源对象的左上角的X坐标</param>
        /// <param name="dwRop">光栅的操作值，真彩含透明窗体请使用CopyPixelOperation.CaptureBlt | CopyPixelOperation.SourceCopy</param>
        /// <returns></returns>
        [DllImport("gdi32.dll")]
        public static extern bool BitBlt(IntPtr hdcDest, int nXDest, int nYDest, int nWidth, int nHeight, IntPtr hdcSrc, int nXSrc, int nYSrc, System.Drawing.CopyPixelOperation dwRop);







//建立屏幕Graphics
            Graphics screenGraphic = Graphics.FromHwnd(IntPtr.Zero);
            //根据屏幕大小建立位图，这就是最后截取到的*屏幕图像*
            Bitmap screenBitmap = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height, screenGraphic);
            //建立位图相关Graphics
            Graphics bitmapGraphics = Graphics.FromImage(screenBitmap);
            //建立屏幕上下文
            IntPtr hdcScreen = screenGraphic.GetHdc();
            //建立位图上下文
            IntPtr hdcBitmap = bitmapGraphics.GetHdc();
            //将屏幕捕获保存在位图中
            Win32API.BitBlt(hdcBitmap, 0, 0, rectangle.Width, rectangle.Height, hdcScreen, rectangle.X, rectangle.Y, CopyPixelOperation.CaptureBlt | CopyPixelOperation.SourceCopy);
            //关闭位图句柄
            bitmapGraphics.ReleaseHdc(hdcBitmap);
            //关闭屏幕句柄
            screenGraphic.ReleaseHdc(hdcScreen);

            //将截图尺寸规格化到指定尺寸
            Bitmap reSizseBitmap = new Bitmap(rectangle.Width, rectangle.Height);
            Graphics reSizeBitmapGraphics = Graphics.FromImage(reSizseBitmap);
            reSizeBitmapGraphics.DrawImage(screenBitmap, new Rectangle(0, 0, rectangle.Width, rectangle.Height), new Rectangle(0, 0, rectangle.Width, rectangle.Height), GraphicsUnit.Pixel);
            //为释放 Graphics 和由 FromImage 方法创建的相关资源，您应该始终调用 Dispose 方法。
            reSizeBitmapGraphics.Dispose();

            //释放位图对像
            bitmapGraphics.Dispose();
            //释放屏幕对像
            screenGraphic.Dispose();


screenBitmap是全屏图像