public Vote Vote(int id) { string Username = HttpContext.Current.Request["LOGON_USER"]; if (!Restaurants.Any(i => i.ID == id)) { throw new Exception("No restaurant exists with that id."); } Restaurant Restaurant = Restaurants.First(i => i.ID == id); var Vote = new Vote(Restaurant, Username); if (this.Votes.Any(i => i.Username == Username && i.Timestamp >= DateTime.Today)) { throw new Exception("You cannot vote twice per day."); } Votes.Add(Vote); return(Vote); }