using System;

using System.IO;

using System.Xml.Serialization;

​

public static class Program

{

    public static void Main(string[] args)

    {

        var some = new SomeClass

        {

            SomeString = "someValue",

            SomeInt = 10

        };

​

        var other = new OtherClass

        {

            OtherString = "someValue",

            OtherInt = 10

        };

​

        Console.WriteLine(ToString(some));

        Console.WriteLine(ToString(other));

    }

​

    private static string ToString(Data data)

    {

        var ser = new XmlSerializer(typeof(Data));

​

        using (var writer = new StringWriter())

        {

            ser.Serialize(writer, data);

            return writer.ToString();

        }

    }

}

​

[XmlRoot("data", Namespace = "http://comp.com/types")]

[XmlInclude(typeof(SomeClass))]

[XmlInclude(typeof(OtherClass))]

public abstract class Data

{

​

}

​

[XmlType(Namespace = "http://comp.com/types")]

public class SomeClass : Data

{

    public string SomeString { get; set; }

    public int SomeInt { get; set; }

}

​

[XmlType(Namespace = "http://comp.com/types")]

public class OtherClass : Data

{

    public string OtherString { get; set; }

    public int OtherInt { get; set; }

}