public bool AddAwardToUser(int userID, int awardID) { if (userID < 1 || awardID < 1) { throw new ArgumentException("ID can't be less than 1"); } if (!userDao.Contains(userID)) { throw new ArgumentException("Can't find user with such ID"); } if (!awardDao.Contains(awardID)) { throw new ArgumentException("Can't find award with such ID"); } if (userDao.AddUserAward(userID, awardID)) { return(true); } throw new InvalidOperationException("on user's award saving"); }