Десериализация XML возвращает пустой массив, хотя POCO имеет правильные атрибуты xml, сгенерированные с помощью инструмента xsd2code++.

Я протестировал код ниже, и он работает. Я вручную создал классы, которые дают более простые результаты, чем использование инструментов.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.Xml.Serialization;
using System.IO;

namespace ConsoleApplication1
{
    class Program
    {
        const string FILENAME = @"c:\temp\test.xml";
        static void Main(string[] args)
        {
            string responseText = File.ReadAllText(FILENAME);
            StringReader reader = new StringReader(responseText);

            XmlReader xReader = XmlReader.Create(reader);
            XmlSerializer serializer = new XmlSerializer(typeof(IntuitResponse));

            IntuitResponse response = (IntuitResponse)serializer.Deserialize(xReader);
        }
    }
    [XmlRoot(ElementName = "IntuitResponse", Namespace = "http://schema.intuit.com/finance/v3")]
    public class IntuitResponse
    {
        [XmlAttribute("time")]
        public DateTime time { get; set; }

        [XmlElement(ElementName = "QueryResponse", Namespace = "http://schema.intuit.com/finance/v3")]
        public QueryResponse response { get; set; }
    }

    public class QueryResponse
    {
        [XmlAttribute("startPosition")]
        public int startPosition { get; set; }
        [XmlAttribute("maxResults")]
        public int maxResults { get; set; }
        [XmlAttribute("totalCount")]
        public int totalCount { get; set; }

        [XmlElement(ElementName = "Invoice", Namespace = "http://schema.intuit.com/finance/v3")]
        public Invoice invoice { get; set; }
    }
    public class Invoice
    {

        [XmlAttribute("domain")]
        public string domain { get; set; }
        [XmlAttribute("sparse")]
        public Boolean sparse { get; set; }

        public int Id { get; set; }
        public int SyncToken { get; set; }

        [XmlElement(ElementName = "MetaData", Namespace = "http://schema.intuit.com/finance/v3")]
        public MetaData metaData { get; set; }

        [XmlElement(ElementName = "CustomField", Namespace = "http://schema.intuit.com/finance/v3")]
        public CustomField customField { get; set; }
        public int DocNumber { get; set; }
        public DateTime TxnDate { get; set; }

        [XmlElement(ElementName = "CurrencyRef", Namespace = "http://schema.intuit.com/finance/v3")]
        public CurrencyRef currencyRef { get; set; }
        public int ExchangeRate { get; set; }
        public string PrivateNote { get; set; }
        [XmlElement(ElementName = "Line", Namespace = "http://schema.intuit.com/finance/v3")]
        public List<Line> line { get; set; }

        [XmlElement(ElementName = "TxnTaxDetail", Namespace = "http://schema.intuit.com/finance/v3")]
        public TxnTaxDetail txnTaxDetail { get; set; }

        [XmlElement(ElementName = "CustomerRef", Namespace = "http://schema.intuit.com/finance/v3")]
        public CustomerRef CustomerRef { get; set; }

        public DateTime DueDate { get; set; }
        public int TotalAmt { get; set; }
        public int HomeTotalAmt { get; set; }
        public Boolean ApplyTaxAfterDiscount { get; set; }
        public string PrintStatus { get; set; }
        public string EmailStatus { get; set; }
        public int Balance { get; set; }
        public int Deposit { get; set; }
        public Boolean AllowIPNPayment { get; set; }
        public Boolean AllowOnlinePayment { get; set; }
        public Boolean AllowOnlineCreditCardPayment { get; set; }
        public Boolean AllowOnlineACHPayment { get; set; }
    }
    public class MetaData
    {
        public DateTime CreateTime { get; set; }
        public DateTime LastUpdatedTime { get; set; }
    }
    public class CustomField
    {

        public int DefinitionId { get; set; }
        public string Name { get; set; }
        public string Type { get; set; }
        public string StringValue { get; set; }
    }
    public class CurrencyRef
    {
        [XmlAttribute("name")]
        public string name { get; set; }

        [XmlText]
        public string value { get; set; }

    }
    public class Line
    {
        public int Id { get; set; }
        public int LineNum { get; set; }
        public string Description { get; set; }
        public decimal Amount { get; set; }
        public string DetailType { get; set; }

        [XmlElement(ElementName = "SalesItemLineDetail", Namespace = "http://schema.intuit.com/finance/v3")]
        public SalesItemLineDetail salesItemLineDetail { get; set; }
    }
    public class CustomerRef
    {
        [XmlAttribute("name")]
        public string name { get; set; }

        [XmlText]
        public string value { get; set; }
    }
    public class SalesItemLineDetail
    {
        [XmlElement(ElementName = "ItemRef", Namespace = "http://schema.intuit.com/finance/v3")]
        public ItemRef itemRef { get; set; }

        public int Qty { get; set; }
        public string TaxCodeRef { get; set; }
    }
    public class ItemRef
    {
        [XmlAttribute("name")]
        public string name { get; set; }

        [XmlText]
        public string value { get; set; }
    }
    public class TxnTaxDetail
    {
        public int TotalTax { get; set; }
    }
}