状态者模式 c#

　　某一对象由于有不同的状态，而产生不同的行为。

 

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;

namespace ConsoleApplication1
{
    class Program
    {

        public interface IDoorState
        {
            void Switch(Door door);
        }

        public class DoorOn : IDoorState
        {
            public void Switch(Door door)
            {
                Console.WriteLine("door off");
                door.DoorState = new DoorOff();
            }
        }

        public class DoorOff : IDoorState
        {
            public void Switch(Door door)
            {
                Console.WriteLine("door on");
                door.DoorState = new DoorOn();
            }
        }

        public class Door
        {
            public IDoorState DoorState
            {
                get;
                set;
            }

            public Door()
            {
                DoorState = new DoorOff();
            }

            public void Switch()
            {
                DoorState.Switch(this);
            }
        }

        static void Main(string[] args)
        {
            Door door = new Door();

            door.Switch();
            door.Switch();
            door.Switch();
        }
    }
}