public void ChangeStatus(Order order) { StringBuilder sqlCmd = new StringBuilder(); if (order.OrderStatus == "Delivered") { order.EndDate = DateTime.Now; sqlCmd.Append($"update ORDERS set OrderStatus = '{order.OrderStatus}', EndDate = '{order.EndDate}' where Id = {order.Id};"); } else { sqlCmd.Append($"update ORDERS set OrderStatus = '{order.OrderStatus}' where Id = {order.Id};"); } OrderMethods.ChangeStatus(Connection, sqlCmd.ToString()); }