网页中插入视频播放器后如果实现截图的功能

 WriteableBitmap wBitmap = new WriteableBitmap(this.media, null);

            Image img = new Image();

            img.Width = 140;

            img.Height = 140;

            img.Margin = new Thickness(5);

            img.Source = wBitmap;      

            ListBoxItem item = new ListBoxItem();

            item.Content = img;

            listBox1.Items.Add(item);

            this.textBlock1.Text = DateTime.Now.ToString();