int i = 0;

           //创建一个htmlweb对象

           HtmlWeb web = new HtmlWeb();

           web.AutoDetectEncoding = true;

           //读取内容返回HtmlAgilityPack.HtmlDocument对象

           HtmlAgilityPack.HtmlDocument doc= web.Load(tBtxt_Url.Text.Trim());

           HtmlNode node = doc.GetElementbyId("post_list");

           //文件流

           StreamWriter sw = File.CreateText("log.txt");



           foreach (HtmlNode child in node.ChildNodes)

           {

               if (child.Attributes["class"] == null || child.Attributes["class"].Value != "post_item")

                   continue;

               HtmlNode hn = HtmlNode.CreateNode(child.OuterHtml);          

               Write(sw, String.Format("推荐：{0}", hn.SelectSingleNode("//*[@class=\"diggnum\"]").InnerText));

               Write(sw, String.Format("标题：{0}", hn.SelectSingleNode("//*[@class=\"titlelnk\"]").InnerText));

               Write(sw, String.Format("介绍：{0}", hn.SelectSingleNode("//*[@class=\"post_item_summary\"]").InnerText));

               Write(sw, String.Format("信息：{0}", hn.SelectSingleNode("//*[@class=\"post_item_foot\"]").InnerText));

               string url = hn.SelectSingleNode("//*[@class=\"titlelnk\"]").Attributes["href"].Value.ToString();

               Write(sw, String.Format("网址：{0}", url));