string d = "http://search.anccnet.com/searchResult2.aspx";

        //name="__VIEWSTATE"  value="/wEPDwULLTEzODQxNzY5NjNkZEc4gDy0wp5ERjILg2b7lTTH3F+w"

        //name="__EVENTVALIDATION"    value="/wEWAwKK7u6vCQLd5eLQCQLmjL2EBxmZU7jWYoh9371phOcBPCjfgdVD"

        //name="keyword"

        //name="gdsBtn"

        Encoding myEncoding = Encoding.GetEncoding("gb2312");

        string param = "__VIEWSTATE=" + HttpUtility.UrlEncode("/wEPDwULLTEzODQxNzY5NjNkZEc4gDy0wp5ERjILg2b7lTTH3F+w", myEncoding)

            + "&" + "__EVENTVALIDATION=" + HttpUtility.UrlEncode("/wEWAwKK7u6vCQLd5eLQCQLmjL2EBxmZU7jWYoh9371phOcBPCjfgdVD", myEncoding)

            + "&" + "keyword=" + HttpUtility.UrlEncode("", myEncoding)

            + "&" + "gdsBtn=" + HttpUtility.UrlEncode("", myEncoding);

        byte[] postBytes = Encoding.ASCII.GetBytes(param);

        HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(d);

        req.Method = "POST";

        req.ContentType = "application/x-www-form-urlencoded;charset=gb2312";

        req.ContentLength = postBytes.Length;

        using (Stream reqStream = req.GetRequestStream())

        {

            reqStream.Write(postBytes, , postBytes.Length);

        }

        string html = "";

        using (WebResponse wr = req.GetResponse())

        {

            Stream stream = wr.GetResponseStream();

            StreamReader sr = new StreamReader(stream,System.Text.Encoding.GetEncoding("gb2312"));

             html = sr.ReadToEnd();

            //在这里对接收到的页面内容进行处理

        }

        Response.Write(html);