public void Unregister(IStockObserverBase observer) { if (_observers.Contains(observer)) { _observers.Remove(observer); } }
public void Register(IStockObserverBase observer) { if (!_observers.Contains(observer)) { _observers.Add(observer); } }
public void Register(IStockObserverBase observer) { if(!_observers.Contains(observer)) { _observers.Add(observer); } }