public static void Update(DiscountCard discountCard) { var date = DateTime.Now; var document = XDocument.Load(Path); var element = document.GetXElements("DiscountCards", "rec").First(el => el.GetXElementValue("CustomerId").ToGuid() == discountCard.CustomerId); DiscountCard.SetXmlValues(element, discountCard); File.WriteAllText(Path, document.ToString()); if (SyncData.IsConnect) { using (var connection = ConnectionFactory.CreateConnection()) connection.Execute(UpdateQuery, new { discountCard.Points, date, discountCard.CustomerId }); } var idx = DiscountCards.FindIndex(ds => ds.CustomerId == discountCard.CustomerId); DiscountCards[idx] = discountCard; }