装饰者模式 c#

　　装饰者模式的目的是给对象附加上更多功能，相对于组合方式，他不需要修改对象源码，相对于继承模式，他更加灵活。

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

namespace ConsoleApplication1
{
    class Program
    {
        /// <summary>
        /// 房子基类
        /// </summary>
        public abstract class House
        {
            public abstract void Print();
        }

        /// <summary>
        /// 我的房子
        /// </summary>
        public class MyHouse : House
        {
            public override void Print()
            {
                Console.WriteLine("this is my house");
            }
        }

        /// <summary>
        /// 房子装饰者
        /// </summary>
        public abstract class Decorator : House
        {
            private House house;

            public Decorator(House house)
            {
                this.house = house;
            }

            public override void Print()
            {
                if (house != null)
                {
                    house.Print();
                }
            }
        }

        public class Window : Decorator
        {
            public Window(House house) : base(house)
            {
            }

            public override void Print()
            {
                base.Print();

                AddWindow();
            }

            /// <summary>
            /// 增加窗户
            /// </summary>
            public void AddWindow()
            {
                Console.WriteLine("add window");
            }
        }

        public class Door : Decorator
        {
            public Door(House house)
                : base(house)
            {
            }

            public override void Print()
            {
                base.Print();

                AddDoor();
            }

            /// <summary>
            /// 增加窗户
            /// </summary>
            public void AddDoor()
            {
                Console.WriteLine("add door");
            }
        }

        static void Main(string[] args)
        {
            House house = new MyHouse();

            //给房子加窗户
            Decorator window = new Window(house);
            window.Print();

            //给房子加门
            Decorator door = new Door(house);
            door.Print();

            //同时加窗户和门
            Decorator doorAndWindow = new Window(door);
            doorAndWindow.Print();
        }
    }
}