using System;

using System.IO;

using System.Text;

using System.Collections.Generic;

using System.Xml.Serialization;

public class Program

{

    public static void Main()

    {

        List<InvoicePair> data = new List<InvoicePair>

            {

                new InvoicePair(new EInvoice{Version="1.03"},new TradeInvoice{Id=1,Value=100}),

                new InvoicePair(new EInvoice{Version="1.03"},new TradeInvoice{Id=2,Value=200}),

                new InvoicePair(new EInvoice{Version="1.03"},new TradeInvoice{Id=3,Value=300})

            };

​

        MemoryStream stream = new MemoryStream();

        Root.Serialize(data, stream);

        Console.WriteLine(Encoding.UTF8.GetString(stream.ToArray()));

        stream.Seek(0, SeekOrigin.Begin);

        var deserialized = Root.Deserialize(stream);

    }

}

​

​

public class InvoicePair

{

    public InvoicePair(EInvoice eInvoice, TradeInvoice tradeInvoice)

    {

        TradeInvoice = tradeInvoice;

        EInvoiceInfo = eInvoice;

    }

    public EInvoice EInvoiceInfo { get; set; }

    public TradeInvoice TradeInvoice { get; set; }

}

​

[XmlRoot("RootXML")]

public class Root

{

    public Root()

    {

        RootBodies = new List<Invoice>();

    }

    [XmlElement(Type = typeof(EInvoice), ElementName = "e-Invoice")]

    [XmlElement(Type = typeof(TradeInvoice), ElementName = "TradeInvoice")]

    public List<Invoice> RootBodies { get; set; }

    public static void Serialize(IEnumerable<InvoicePair> invoices, Stream stream)

    {

        Root root = new Root();

        foreach (var invoice in invoices)

        {

            root.RootBodies.Add(invoice.EInvoiceInfo);

            root.RootBodies.Add(invoice.TradeInvoice);

        }

        XmlSerializer serializer = new XmlSerializer(typeof(Root));

        serializer.Serialize(stream, root);

    }

    public static IEnumerable<InvoicePair> Deserialize(Stream stream)

    {

        XmlSerializer serializer = new XmlSerializer(typeof(Root));

        Root root = serializer.Deserialize(stream) as Root;

        for (int i = 0; i < root.RootBodies.Count; i += 2)

        {

            yield return new InvoicePair((EInvoice) root.RootBodies[i], (TradeInvoice) root.RootBodies[i+1]);

        }

    }

}

​

[XmlInclude(typeof(EInvoice))]

[XmlInclude(typeof(TradeInvoice))]

public abstract class Invoice

{

}

​

[XmlRoot("e-Invoice")]

public class EInvoice : Invoice

{

    [XmlElement("Version")]

    public string Version { get; set; }

}

​

[XmlRoot("TradeInvoice")]

public class TradeInvoice : Invoice

{

    [XmlElement("Id")]

    public int Id { get; set; }

    [XmlElement("Value")]

    public int Value { get; set; }

}