public String ChatMessages([FromForm] int id) { List <ChatMessage> msgs = _cdb.GetChatMessages(id); List <ChatMessageModel> rm = new List <ChatMessageModel>(); List <String> ids = msgs.Select(x => x.SenderId).Distinct().ToList(); List <IdentityUser> users = _db.Users.Where(x => ids.Contains(x.Id)).ToList(); msgs.ForEach(x => { ChatMessageModel cmm = new ChatMessageModel(); cmm.UserId = x.SenderId; cmm.MessageText = x.MessageText; cmm.MessageTime = x.SentTime; //ToDo: cmm.UserEmail = users.Where(y => y.Id == x.SenderId).Single().Email; rm.Add(cmm); }); //O(n) return(""); }