private void BuildReceipt(TreeNode root, ReceiptHeader receipt)
        {
            // позиции чека
            foreach (KeyValuePair<ReceiptRowKey, ReceiptRow> kvp in receipt.GetRowEnumerable())
            {
                TreeNode rowNode = new TreeNode(kvp.Value.ToString(), 6, 6);
                rowNode.Tag = kvp.Value;
                BuildDiscounts(rowNode, kvp.Value.GetAutoDiscountsEnumerable(), "Авт.");
                BuildDiscounts(rowNode, kvp.Value.GetPersonalDiscountEnumerable(), "Перс.");
                root.Nodes.Add(rowNode);
            }

            // использованные платежные карты
            foreach (KeyValuePair<String, PaymentCard> kvp in receipt.GetCardEnumerable())
            {
                TreeNode cardNode = new TreeNode(kvp.Value.ToString(), 7, 7);
                cardNode.Tag = kvp.Value;
                root.Nodes.Add(cardNode);
            }
        }