WindowsFormsApplication1.Form1.createChatRoom C# (CSharp) Méthode

        private Tuple<string, List<string>, List<string>, string> createChatRoom(List<string> user_names)
        {
            var member_list = new List<Dictionary<string, dynamic>>();
            user_names.ForEach(username => 
            {
                var mem = new Dictionary<string, dynamic>();
                mem.Add("UserName", username);
                member_list.Add(mem);
            });

            var url = base_url + String.Format("webwxcreatechatroom?pass_ticket={0}&r={1}", pass_ticket, get_timestamp());
            var http = WebRequest.Create(url) as HttpWebRequest;
            http.CookieContainer = cookieContainer;
            http.ContentType = "application/json; charset=UTF-8";
            http.Method = "POST";
            var serializer = new JavaScriptSerializer();
            var base_req_param = new { Uin = Int64.Parse(wxuin), Sid = wxsid, Skey = skey, DeviceID = deviceId };
            var payload = serializer.Serialize(new { BaseRequest = base_req_param, MemberCount = member_list.Count,
                                                         MemberList = member_list, Topic = ""});
            Console.WriteLine(payload);
            var response = getPostResponse(http, payload);
            var dic = deserilizeJson(response);
            var room_name = dic["ChatRoomName"];
            member_list = new List<Dictionary<string, dynamic>>(dic["MemberList"].
                                                           ToArray(typeof(Dictionary<string, dynamic>)));
            var deleted_list = new List<string>();
            var blocked_list = new List<string>();
            member_list.ForEach(member =>
            {
                if ((int) member["MemberStatus"] == 4)
                {
                    deleted_list.Add(member["UserName"]);
                }
                else if ((int) member["MemberStatus"] == 3)
                {
                    blocked_list.Add(member["UserName"]);
                }
            });

            string err_msg = dic["BaseResponse"]["ErrMsg"];
            return Tuple.Create(room_name, deleted_list, blocked_list,err_msg);
        }