C# List<Object>值拷贝

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.Serialization.Formatters.Binary;
using System.Text;
namespace ConsoleApplication1
{
    public class Program
    {
        public static void Main(string[] args)
        {
            ItemList listBefore = (ItemList)new List<Item>();
            listBefore.Add(new Item() { ID = 12, Name = "张三" });
            listBefore.Add(new Item() { ID = 18, Name = "李四" });
            ItemList listAfter = new ItemList();
            listAfter = (ItemList)listBefore.Clone();
            Console.WriteLine("Before  未修改" + listBefore[0].ID);
            Console.WriteLine("Before  未修改" + listBefore[0].Name);
            Console.WriteLine();
            Console.WriteLine();
            Console.WriteLine("After  未修改" + listAfter[0].ID);
            Console.WriteLine("After  未修改" + listAfter[0].Name);
            Console.WriteLine();
            Console.WriteLine();
            listAfter[0].ID = 110;
            listAfter[0].Name = "小孩";
            Console.WriteLine("Before  以修改" + listBefore[0].ID);
            Console.WriteLine("Before  以修改" + listBefore[0].Name);
            Console.WriteLine();
            Console.WriteLine();
            Console.WriteLine("After  以修改" + listAfter[0].ID);
            Console.WriteLine("After  以修改" + listAfter[0].Name);
            Console.WriteLine();
            Console.WriteLine();
        }
    }
    [Serializable]
    public class Item
    {
        public int ID { get; set; }
        public string Name { get; set; }
    }
    [Serializable]
    public class ItemList : List<Item>, ICloneable
    {
        public object Clone()
        {
            MemoryStream ms = new MemoryStream();
            object obj;
            try
            {
                BinaryFormatter bf = new BinaryFormatter();
                bf.Serialize(ms, this);
                ms.Seek(0, SeekOrigin.Begin);
                obj = bf.Deserialize(ms);
            }
            finally
            {
                ms.Close();
            }
            return obj;
        }
    }
}