public void DeleteTransaction(int transactionId) { SaleManager sm = new SaleManager(); List <Sale> sales = sm.GetSalesByTransactionID(transactionId); foreach (Sale s in sales) { sm.DeleteSale(s.ID); } sales.Clear(); sm = null; PaymentManager pm = new PaymentManager(); Payment p = pm.GetPaymentByTransactionID(transactionId); pm.DeletePayment(p.ID); p = null; pm = null; TransactionCache.GetInstance().DeleteTransaction(transactionId); }