备忘录模式

/*
 *
 * User: Administrator
 * Date: 2007-7-2
 * Time: 9:02
 */
using System;
using System.Collections.Generic;

namespace myMemonto
{

    public interface IMemonto{}

    public class State
    {
        public State(){}
        public string stateName;//状态名
        public int Level;//状态级别
    }

    //发起者
    public class Originator
    {
        private class Memonto:IMemonto
        {
            private State _state;
            public Memonto(State st)
            {
                _state=new State();
                _state.stateName=st.stateName;
                _state.Level=st.Level;
            }
        public State state
        {
            get{
                return _state;
            }
            set{
                _state=value;
            }
        }

        }




        private State state;

        public Originator()
        {
            state=new State();
            state.stateName="begin";
            state.Level=1;
        }
        public string StateName
        {
            get{return state.stateName;}
            set{state.stateName=value;}
        }
        public int Level
        {
            get
            {
                return state.Level;
            }
            set
            {
                state.Level=value;
            }
        }
        public IMemonto CreateMomento()    {
            return new Memonto(this.state);
        }
        public void SetState(IMemonto m)
        {
            Memonto mm=(Memonto)m;
            this.state=mm.state;
        }

    }

    public class Caretaker:System.Collections.CollectionBase
    {
        public Caretaker(){}
        public int Add(IMemonto st)
        {
            return List.Add(st);
        }
        public IMemonto this[int index]{
            get{
                return (IMemonto)List[index];
            }

            set{
                List[index]=value;
            }
        }
        public void Remove(IMemonto st){
            List.Remove(st);
        }
        public IMemonto Restore()
        {
            if(List.Count==0) return null;
            IMemonto st=(IMemonto) List[List.Count-1];
            List.Remove(st);
            return st;
        }
    }



    class MainClass
    {
        public static void Main(string[] args)
        {
            //Console.WriteLine("Hello World!");
            Originator o=new Originator();
            Caretaker c=new Caretaker();
            c.Add(o.CreateMomento());

            o.StateName="one";
            o.Level=100;

            c.Add(o.CreateMomento());

            o.StateName="two";
            o.Level=200;

            c.Add(o.CreateMomento());

            IMemonto m=c.Restore();

            while(m!=null){
                o.SetState(m);
                System.Console.WriteLine(o.StateName);
                m=c.Restore();
            }
            System.Console.ReadLine();
        }
    }
}