前言

我昨天做了个梦，我梦见我在一条路走，走的时候经过一个房间，里面关着一条边牧和鸡和猪，后来我醒了，我知道那只边牧就是小叶子(哈仔十一的边牧)，小叶子具备牧羊和牧鸡的技能，因此，假如我想把一只边牧或者一只狗变成小叶子那样，那么首先就得让其赋予牧鸡的本事，而十一(哈仔十一的哈士奇)则具备卖萌的技能

适配器模式

我们先定义一些代码

    internal interface IDog
    {
        public void Eat();

        public void Bark();
    }


    /// <summary>
    /// 哈士奇
    /// </summary>
    internal interface IHuskyDog:IDog
    {
        /// <summary>
        /// 破坏、拆家
        /// </summary>
        public void Demolition();
    }

    /// <summary>
    /// 牧羊犬
    /// </summary>
    internal interface IShepherdDog:IDog
    {
        /// <summary>
        /// 牧羊
        /// </summary>
        public void Shepherd();
    }



    /// <summary>
    /// 小叶子、小椰汁
    /// </summary>
    internal class XiaoYezi : IShepherdDog
    {
        public void Bark()
        {
            Console.WriteLine($"I Am {nameof(XiaoYezi)} 汪 汪 汪 !!!!!");
        }

        public void Eat()
        {
            Console.WriteLine($"I Am {nameof(XiaoYezi)} 好吃 !!!!!");
        }

        /// <summary>
        /// 牧羊
        /// </summary>
        public void Shepherd()
        {
            Console.WriteLine($"I Am {nameof(XiaoYezi)}， 我在牧羊 !!!!!");
        }
    }


    /// <summary>
    /// 十一
    /// </summary>
    internal class ShiYi : IHuskyDog
    {
        public void Bark()
        {
            Console.WriteLine($"I Am {nameof(ShiYi)} 汪 汪 汪 !!!!!");
        }

        public void Demolition()
        {
            Console.WriteLine($"I Am {nameof(ShiYi)} ,拆家啦 !!!!!");
        }

        public void Eat()
        {
            Console.WriteLine($"I Am {nameof(ShiYi)} 好吃得停不下来 !!!!!");
        }
    }

那么，用代码怎么写呢？或许你会定义一个变叶子的接口，有个方法叫HerdingChicken ,让其实现牧鸡的技能就行，但是实际上这里有两个主要问题：

• 叶子本身是一个狗，如果其他人实现了这个接口，他能变叶子？是不是前提他是狗
• 假如叶子不单单只是牧鸡，她会牧鹅、猪、牧自己？还得多接口，或者在变叶子的接口加方法给其实现

这时候适配器模式就是可以适应这种情况：

 internal class XiaoYeziAdapter : IShepherdDog
    {
        public IDog Dog { get; set; }

        public XiaoYeziAdapter(IDog dog)
        {
            Dog = dog;
        }

        public void Bark()
        {
            Dog.Bark();
        }

        public void Eat()
        {
            Dog.Eat();
        }

        public void Shepherd()
        {
            if (Dog is IShepherdDog shepherdDog)
            {
                shepherdDog.Shepherd();
            }
        }

        /// <summary>
        /// 牧鸡
        /// </summary>
        public void HerdingChicken()
        {
            Console.WriteLine($"{Dog.GetType().Name} is Herding Chicken");
        }
    }

代码如下：

var xiaoYezi = new XiaoYezi();
var xiaoYeziAdapter = new XiaoYeziAdapter(xiaoYezi);
xiaoYeziAdapter.Bark();
xiaoYeziAdapter.Eat();
xiaoYeziAdapter.HerdingChicken();

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

var shiYi = new ShiYi();
xiaoYeziAdapter = new XiaoYeziAdapter(shiYi);
xiaoYeziAdapter.Bark();
xiaoYeziAdapter.Eat();
xiaoYeziAdapter.HerdingChicken();

输出：

I Am XiaoYezi 汪 汪 汪 !!!!!
I Am XiaoYezi 好吃 !!!!!
XiaoYezi 在牧鸡
----------------

I Am ShiYi 汪 汪 汪 !!!!!
I Am ShiYi 好吃得停不下来 !!!!!
ShiYi 在牧鸡

可以看到，十一用了小叶子适配器，也具备了牧鸡的功能

那么反过来，叶子变十一呢？那就定义一个十一适配器呗

 internal class ShiYiAdapter : IHuskyDog
    {
        public IDog Dog { get; set; }

        public ShiYiAdapter(IDog dog)
        {
            Dog=dog;
        }

        /// <summary>
        /// 吠
        /// </summary>
        /// <exception cref="NotImplementedException"></exception>
        public void Bark()
        {
            Dog.Bark();
        }

        /// <summary>
        /// 拆家
        /// </summary>
        /// <exception cref="NotImplementedException"></exception>
        public void Demolition()
        {
            if (Dog is IHuskyDog huskyDog)
            {
                huskyDog.Demolition();
            }
        }

        /// <summary>
        /// 吃
        /// </summary>
        /// <exception cref="NotImplementedException"></exception>
        public void Eat()
        {
            Dog.Eat();
        }

        /// <summary>
        /// 卖萌
        /// </summary>
        public void ActingCute()
        {
            Console.WriteLine($"{Dog.GetType().Name} 卖萌啦！！");
        }
    }

代码如下：

var xiaoYezi = new XiaoYezi();
var shiYiAdapter = new ShiYiAdapter(xiaoYezi);
shiYiAdapter.Bark();
shiYiAdapter.ActingCute();
shiYiAdapter.Demolition();

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

var shiYi = new ShiYi();
shiYiAdapter = new ShiYiAdapter(shiYi);
shiYiAdapter.Bark();
shiYiAdapter.ActingCute();
shiYiAdapter.Demolition();

输出：

I Am XiaoYezi 汪 汪 汪 !!!!!
XiaoYezi 卖萌啦！！
----------------

I Am ShiYi 汪 汪 汪 !!!!!
ShiYi 卖萌啦！！
I Am ShiYi ,拆家啦 !!!!!

看，小叶子具备卖萌的技能了，而且由于拆家是哈士奇的技能，因此小叶子拆家没拆到，实际上，或者卖萌和牧鸡只是哈仔十一(大哈)家的特色，那么是不是可以定义一个大哈家的适配器

    /// <summary>
    /// 哈仔十一家的狗适配器
    /// </summary>
    internal class DaHaFamilyDogAdapter
    {
        public IDog Dog { get; set; }

        public DaHaFamilyDogAdapter(IDog dog)
        {
            Dog = dog;
        }

        /// <summary>
        /// 牧鸡
        /// </summary>
        public void HerdingChicken()
        {
            Console.WriteLine($"{Dog.GetType().Name} 在牧鸡");
        }

        /// <summary>
        /// 卖萌
        /// </summary>
        public void ActingCute()
        {
            Console.WriteLine($"{Dog.GetType().Name} 在卖萌");
        }
    }

那么

var xiaoYezi = new XiaoYezi();
var daHaFamilyDogAdapter = new DaHaFamilyDogAdapter(xiaoYezi);
daHaFamilyDogAdapter.Bark();
daHaFamilyDogAdapter.Eat();
daHaFamilyDogAdapter.HerdingChicken();
daHaFamilyDogAdapter.ActingCute();

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

var shiYi = new ShiYi();
daHaFamilyDogAdapter = new DaHaFamilyDogAdapter(shiYi);
daHaFamilyDogAdapter.Bark();
daHaFamilyDogAdapter.Eat();
daHaFamilyDogAdapter.HerdingChicken();
daHaFamilyDogAdapter.ActingCute();

输出：

I Am XiaoYezi 汪 汪 汪 !!!!!
I Am XiaoYezi 好吃 !!!!!
XiaoYezi 在牧鸡
XiaoYezi 在卖萌
----------------

I Am ShiYi 汪 汪 汪 !!!!!
I Am ShiYi 好吃得停不下来 !!!!!
ShiYi 在牧鸡
ShiYi 在卖萌