winfrom(C#) Post提交(带参数)，返回值

public void PostMoths()        {            string strURL = "http://www.cqjg.gov.cn/newwww/c7/clwz.asp";            System.Net.HttpWebRequest request;            request = (System.Net.HttpWebRequest)WebRequest.Create(strURL);            //Post请求方式            request.Method = "POST";            //内容类型            request.ContentType = "application/x-www-form-urlencoded";            //参数经过URL编码            string paraUrlCoded = System.Web.HttpUtility.UrlEncode("LicenseTxt");            paraUrlCoded += "=" + System.Web.HttpUtility.UrlEncode(txtCarId .Text.Trim());            paraUrlCoded +="& "+ System.Web.HttpUtility.UrlEncode("VIN");            paraUrlCoded += "=" + System.Web.HttpUtility.UrlEncode(txtCarNumber.Text.Trim());            byte[] payload;            //将URL编码后的字符串转化为字节            payload = System.Text.Encoding.UTF8.GetBytes(paraUrlCoded);            //设置请求的ContentLength             request.ContentLength = payload.Length;            //获得请求流            Stream writer = request.GetRequestStream();            //将请求参数写入流            writer.Write(payload, 0, payload.Length);            //关闭请求流            writer.Close();            System.Net.HttpWebResponse response;            //获得响应流            response = (System.Net.HttpWebResponse)request.GetResponse();            System.IO.Stream s;            s = response.GetResponseStream();            string StrDate = "";            string strValue = "";            StreamReader Reader = new StreamReader(s,Encoding.Default);            while ((StrDate= Reader.ReadLine())!=null)            {                strValue += StrDate+"\r\n";            }            // txtInfo.Text = strValue;            txtInfo.Text= FindContent(strValue);            //XmlTextReader Reader = new XmlTextReader(s);            //Reader.MoveToContent();            //string strValue = Reader.ReadInnerXml();            //strValue = strValue.Replace("<", "<");            //strValue = strValue.Replace(">", ">");            //MessageBox.Show(strValue);            //Reader.Close();        }