winform c# 请求网站，返回Json字符串

  private void callApibjhb()
         {
              //输出执行的开始时间
             Console.WriteLine(string.Format("Bind {0}", DateTime.Now));
             Thread T = new Thread(() =>
          {  //表示不停刷新，如果不需要可以删除
                 while (true) {  

                     string strURL = "";
                     try
              {
                System.GC.Collect();
                         string strURL =“你请求的网址”;
             System.Net.HttpWebRequest request;
                         // 创建一个HTTP请求
                         request = (System.Net.HttpWebRequest)WebRequest.Create(strURL);
                         request.Method = "GET";
                         request.Timeout = ;
                         request.ContentType = "application/json;charset=UTF-8";
                         request.ServicePoint.Expect100Continue = false;
                         request.KeepAlive = false;
                         System.Net.ServicePointManager.DefaultConnectionLimit = ;
             System.Net.HttpWebResponse response;
                         response = (System.Net.HttpWebResponse)request.GetResponse();
                         Stream myResponseStream = response.GetResponseStream();
                         StreamReader myStreamReader = new StreamReader(myResponseStream, Encoding.GetEncoding("utf-8"));
                         string retString = myStreamReader.ReadToEnd();
                         Console.WriteLine("ret string === {0}+  {1}", retString, strURL);
                         //创建RepParambj28hb类，字段格式是：根据“请求网站返回的Json字符串”，到网上搜“在线Json格式化”去解析
                         RepParambj28hb rep = JsonConvert.DeserializeObject<RepParambj28hb>(retString);
                         for (int i = ; i < rep.result.lotterys.Length; i++)
                {
                                      //根据自己的需求，得到值
                                     string jh = rep.result.lotterys[i].opencode.Replace(",", "");
                                     dt.Rows[dt.Rows.Count - ]["cl1"] = rep.result.lotterys[i].expect;
                   }
                   myStreamReader.Close();
                   myResponseStream.Close();

                     }
                     catch (Exception webEx)
                     {
                     }
                 }
             });

             T.Start();
            Console.WriteLine(string.Format("Bind end {0}", DateTime.Now));
         }