public void Add(Level level) { if (level == null) throw new ArgumentNullException("level"); if (_levels.ContainsValue(level)) throw new Exception("This level is already added."); level.SetLevelNumber(LastLevelNumber + 1); _levels.Add(level.LevelNumber, level); }
public void Replace(Level oldLevel, Level newLevel) { newLevel.SetLevelNumber(oldLevel.LevelNumber); _levels[oldLevel.LevelNumber] = newLevel; }