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 = 600000;
                        request.ContentType = "application/json;charset=UTF-8";
                        request.ServicePoint.Expect100Continue = false;
                        request.KeepAlive = false;
                        System.Net.ServicePointManager.DefaultConnectionLimit = 50;
            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 = 0; 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 - 1]["cl1"] = rep.result.lotterys[i].expect;
                  }      
                  myStreamReader.Close();
                  myResponseStream.Close();

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