Someone

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

namespace test
{
    public class World
    {
        public int a;
        static World world;

        static void Main(string[] args)
        {
            //Create
            World w = new World();
            w.a = 5;

            //Save
            world = w;
            Save();

            //Load
            //Load();
            //Console.WriteLine("Loaded World a:{0}", world.a);
        }

        static void Load()
        {
            TextReader file = new StreamReader("World.xml");
            XmlSerializer serializer = new XmlSerializer(typeof(World));
            world = (World)serializer.Deserialize( file);
        }

        static void Save()
        {
            TextWriter file = new StreamWriter("World.xml");
            XmlSerializer serializer = new XmlSerializer(typeof(World));
            serializer.Serialize(file, world);
        }
    }
}