using System;

using System.IO;

using System.Text;

using System.Xml.Serialization;

public class Program

{

    public static void Main()

    {

        var dummy = new Dummy {TimeSpan = TimeSpan.FromMilliseconds(1)};

        var stringBuilder = new StringBuilder();

        var serializer = new XmlSerializer(dummy.GetType());

        using (var writer = new StringWriter(stringBuilder))

        {

            serializer.Serialize(writer, dummy);

        }

        var xml = stringBuilder.ToString();

        Console.Write(xml);

    }

    public class Dummy

    {

        public TimeSpan TimeSpan { get; set; }

    }

}