public void AddToExistingPurchase(int PurchaseID, int UserID) { Stocky.Proxies.AppDataClient DataClient = new Proxies.AppDataClient(); try { if (IsObjectValid) { DataClient.Open(); DataClient.AddToExistingPurchase(this, PurchaseID, UserID); OnStockCreated(); } else { throw new InvalidObjectException(PropertyList); } } finally { DataClient.Close(); } }