public bool UnsubscribeFromPriceChangedEvent() { try { IProductsServiceCallback callback = OperationContext.Current.GetCallbackChannel <IProductsServiceCallback>(); subscribers.Remove(callback); return(true); } catch (Exception) { return(false); } }
public bool SubscribeToPriceChangedEvent() { try { IProductsServiceCallback callback = OperationContext.Current.GetCallbackChannel <IProductsServiceCallback>(); if (!subscribers.Contains(callback)) { subscribers.Add(callback); } return(true); } catch (Exception) { return(false); } }