黄色的是wpf控件的名称！

         //保存到特定路径

            FileStream fs = new FileStream(@"C:\image.png", FileMode.Create);

            //对象转换成位图

            RenderTargetBitmap bmp = new RenderTargetBitmap((int)this.mediaElement1.ActualWidth, (int)this.mediaElement1.ActualHeight, 100, 100, PixelFormats.Pbgra32);

            bmp.Render(this.mediaElement1);

            //对象的集合编码转成图像流

            BitmapEncoder encoder = new PngBitmapEncoder();

            encoder.Frames.Add(BitmapFrame.Create(bmp));

            //保存到路径中

            encoder.Save(fs);

            //释放资源

            fs.Close();

            fs.Dispose();

 

//第二个截取全屏

    Image myImage = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height);

            Graphics g = Graphics.FromImage(myImage);

            g.CopyFromScreen(new Point(0, 0), new Point(0, 0), new Size(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height));

            IntPtr dc1 = g.GetHdc(); //此处这两句多余，具体看最后GetHdc()定义

            g.ReleaseHdc(dc1);

            g.Dispose();          

             myImage.Save(@"C:\image.png",System.Drawing.Imaging.ImageFormat.Png);

原作者  http://blog.sina.com.cn/s/blog_8bf5ef0d01013wli.html