public static void getContList(string uid)
 {
     if (socket != null)
     {
         ContSign contSign = new ContSign();
         contSign.user = uid;
         contSign.sign = "";
         string json = JsonConvert.SerializeObject(contSign);
         socket.Emit("getContList", json);
     }
 }
 public static void signature(string uid, string sign)
 {
     if (socket != null)
     {
         ContSign contSign = new ContSign();
         contSign.user = uid;
         contSign.sign = "PowerBy_" + uid;
         string json = JsonConvert.SerializeObject(contSign);
         socket.Emit("signature", json);
     }
 }