WPF 获取拖拽网页图片链接

在浏览器里拖拽一个元素，我只获取图片链接

  private void Grid_PreviewDragOver(object sender, DragEventArgs e)
        {
            e.Effects = DragDropEffects.All;
            e.Handled = true;
        }
        private void Grid_PreviewDrop(object sender, DragEventArgs e)
        {
            string url = "";
            //var mm= e.Data.GetFormats();
            //var f = e.Data.GetData(DataFormats.StringFormat, true);
            /*
                if (e.Data.GetDataPresent(DataFormats.StringFormat, true))
                {
                   url = e.Data.GetData(DataFormats.StringFormat) as string;
                    MessageBox.Show(url);
                    //SavePic(url);
                }*/

            try
            {
                var html = ""+e.Data.GetData(DataFormats.Html, true);
                //src="
                Regex reg = new Regex("src=\"(?<pic>[^\"]+)\"");
                Match mc = reg.Match(html);
                if (!mc.Success)
                {
                    return;
                }
                url=mc.Groups["pic"].Value;
                MessageBox.Show(url);
                SavePic(url);

            }
            catch { 

            }

        }