9.装饰者模式(Decorator Pattern)

using System;



namespace ConsoleApplication7

{

    class Program

    {

        static void Main(string[] args)

        {

            // 我买了个苹果手机

            Phone phone = new ApplePhone();



            // 现在想贴膜了

            Decorator applePhoneWithSticker = new Sticker(phone);



            // 扩展贴膜行为

            applePhoneWithSticker.Print();

            Console.WriteLine("----------------------\n");



            // 现在我想有挂件了

            Decorator applePhoneWithAccessories = new Accessories(phone);



            // 扩展手机挂件行为

            applePhoneWithAccessories.Print();

            Console.WriteLine("----------------------\n");



            // 现在我同时有贴膜和手机挂件了

            Sticker sticker = new Sticker(phone);

            Accessories applePhoneWithAccessoriesAndSticker = new Accessories(sticker);

            applePhoneWithAccessoriesAndSticker.Print();

            Console.ReadLine();

        }

    }



    /// <summary>

    /// 手机抽象类，即装饰者模式中的抽象组件类

    /// </summary>

    public abstract class Phone

    {

        public abstract void Print();

    }



    /// <summary>

    /// 苹果手机，即装饰着模式中的具体组件类

    /// </summary>

    public class ApplePhone : Phone

    {

        /// <summary>

        /// 重写基类方法

        /// </summary>

        public override void Print()

        {

            Console.WriteLine("开始执行具体的对象——苹果手机");

        }

    }



    /// <summary>

    /// 装饰抽象类,要让装饰完全取代抽象组件，所以必须继承自Photo

    /// </summary>

    public abstract class Decorator : Phone

    {

        private Phone phone;



        public Decorator(Phone p)

        {

            this.phone = p;

        }



        public override void Print()

        {

            if (phone != null)

            {

                phone.Print();

            }

        }

    }



    /// <summary>

    /// 贴膜，即具体装饰者

    /// </summary>

    public class Sticker : Decorator

    {

        public Sticker(Phone p)

            : base(p)

        {

        }



        public override void Print()

        {

            base.Print();





            // 添加新的行为

            AddSticker();

        }



        /// <summary>

        /// 新的行为方法

        /// </summary>

        public void AddSticker()

        {

            Console.WriteLine("现在苹果手机有贴膜了");

        }

    }



    /// <summary>

    /// 手机挂件

    /// </summary>

    public class Accessories : Decorator

    {

        public Accessories(Phone p)

            : base(p)

        {

        }



        public override void Print()

        {

            base.Print();



            // 添加新的行为

            AddAccessories();

        }



        /// <summary>

        /// 新的行为方法

        /// </summary>

        public void AddAccessories()

        {

            Console.WriteLine("现在苹果手机有漂亮的挂件了");

        }

    }

}