設計模式----裝飾模式

  裝飾模式(Decorator Pattern):動態的給一個對象添加一些額外的職責，就增加功能來說，裝飾模式比生成子類更爲靈活。

實例: 顯示一個人的穿衣

第一版: 直接使用一個Person類來實現穿衣

                                   

第二版: 把人和服飾類分開了，穿衣的一些表現通過繼承與服飾類 

    

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

namespace Decorate  
{                                                       
    class Person
    {
        private string name;
        public Person(string name)
        {
            this.name = name;
        }
        public void Show()
        {
            Console.Write(" 裝扮的{0}", name);
        }

    }
}

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

namespace Decorate
{
    abstract class Finery  //n. 華麗、優雅的服裝或裝飾，作爲父類  
    {
        public abstract void Show();
    }
}

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

namespace Decorate
{
    class TShirts:Finery
    {
        public override void Show()
        {
            Console.Write(" 大T恤 ");
            //throw new NotImplementedException();
        }
    }
    class BigTrouser:Finery
    {
         public override void  Show()
        {
 	        Console.Write(" 垮褲");
             //throw new NotImplementedException();
         }
    }
    class Sneakers:Finery
    {
        public override void  Show()
        {
            Console.Write(" 球鞋");
         	//throw new NotImplementedException();
        }
    }
    class Tie:Finery
    {
        public override void  Show()
        {
            Console.Write(" 領帶");
 	        //throw new NotImplementedException();
        }
    }
    class LeatherShoes:Finery
    {
        public override void  Show()
        {
            Console.Write(" 皮鞋");
        }
    }
}

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

namespace Decorate  
{
    class Program
    {
        static void Main(string[] args)
        {
          /*  Person xc = new Person("小菜");
            Console.Write("第一種裝扮:\n");`
            xc.WearTShirt();
            xc.WearBigTrouser();
            xc.WearSneakers();
            xc.Show();

            Console.Read();
           */
            Person xc = new Person("小菜");
            Finery dtx = new TShirts();
            Finery kk = new BigTrouser();
            Finery pqx = new Sneakers();

            dtx.Show();
            kk.Show();
            pqx.Show();
            xc.Show();

            Console.Read();

        }
    }
}

第三版： 使用裝飾模式 

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

namespace Decorate  
{
    class Program
    {
        static void Main(string[] args)
        {
          /*  Person xc = new Person("小菜");
            Console.Write("第一種裝扮:\n");`
            xc.WearTShirt();
            xc.WearBigTrouser();
            xc.WearSneakers();
            xc.Show();

            Console.Read();
           */
          /*  Person xc = new Person("小菜");
            Finery dtx = new TShirts();
            Finery kk = new BigTrouser();
            Finery pqx = new Sneakers();

            dtx.Show();
            kk.Show();
            pqx.Show();
            xc.Show();
           */
            Person xc = new Person("小菜");
            Sneakers pqx = new Sneakers(); /// 使用的Person的構造函數構造的
            BigTrouser kk = new BigTrouser();
            TShirts dtx = new TShirts();

            // 裝飾過程
            pqx.Decorate(xc);
            kk.Decorate(pqx);
            dtx.Decorate(kk);
            dtx.Show();

            Console.Read();

        
        }
    }
}


// 人類
class Person
{
    public Person()
    {
    }
    private string name;
    public Person(string name)
    {
        this.name = name;
    }
    public virtual void Show()
    {
        Console.WriteLine(" 裝扮的{0}", name);
    }

}


//  裝飾類
class Finery : Person
{
    protected Person component; /// 成分，零件，組成
    public void Decorate(Person component)
    {
        this.component = component;
    }
    public override void Show()
    {
        if (component != null)
        {
            component.Show();
        }
    }
}

class TShirts : Finery
{
    public override void Show()
    {
        Console.Write(" 大T恤 ");
        base.Show();
        //throw new NotImplementedException();
    }
}
class BigTrouser : Finery
{
    public override void Show()
    {
        Console.Write(" 垮褲");
        base.Show();
        //throw new NotImplementedException();
    }
}
class Sneakers : Finery
{
    public override void Show()
    {
        Console.Write(" 球鞋");
        base.Show();
        //throw new NotImplementedException();
    }
}
class Tie : Finery
{
    public override void Show()
    {
        Console.Write(" 領帶");
        base.Show();
        //throw new NotImplementedException();
    }
}
class LeatherShoes : Finery
{
    public override void Show()
    {
        Console.Write(" 皮鞋");
        base.Show();
    }
}

裝飾模式總結： 把類中的裝飾功能從類中搬移出去，可以簡化類，能有效的吧核心職責和裝飾功能分開。取出相關類的裝飾邏輯。