public void LoadData() { Customer.PurchaseHistory.Clear(); foreach (Purchase purchase in PurchaseManager.GetAllById(Customer.Info.Id, "CustomerId")) { Customer.PurchaseHistory.Add(new PurchaseHistory(purchase)); } foreach (PurchaseHistory purchaseHistory in Customer.PurchaseHistory) { foreach (PurchaseItem purchaseItem in PurchaseItemManager.GetAllById(purchaseHistory.Purchase.Id, "PurchaseId")) { purchaseHistory.PurchaseDetails.Add(new PurchaseDetails(purchaseItem, ItemManager.GetById(purchaseItem.ItemId, "Id"))); } } }