设计模式-装饰模式

Decorator Pattern

装饰模式：装饰模式主要是解决了，我们以动态的，透明的形式为某个类型添加一个新的职责，客户程序可以不知道我们具体添加的功能职责，

而客户程序只是根据对象提供的方法进行调用即可。而具体职责操作留给装饰对象去完成。

  abstract class Component
    {
        public abstract void Operation();
    }

    class ConcreteComponent : Component
    {
        public override void Operation()
        {
            Console.WriteLine("具体对象的操作");
        }
    }

    abstract class Decorator : Component
    {
        protected Component component;

        public void SetComponent(Component component)
        {
            this.component = component;
        }

        public override void Operation()
        {
            if (component != null)
            {
                component.Operation();
            }
        }
    }

    class ConcreteDecoratorA : Decorator
    {
        private string addedState;

        public override void Operation()
        {
            base.Operation();
            addedState = "New State";
            Console.WriteLine("具体装饰对象A的操作");
        }
    }

    class ConcreteDecoratorB : Decorator
    {

        public override void Operation()
        {
            base.Operation();
            AddedBehavior();
            Console.WriteLine("具体装饰对象B的操作");
        }

        private void AddedBehavior()
        {

        }
    }

客户端调用：

ConcreteComponent c = new ConcreteComponent();

ConcreteDecoratorA d1 = new ConcreteDecoratorA();
ConcreteDecoratorB d2 = new ConcreteDecoratorB();

d1.SetComponent(c);
d2.SetComponent(d1);
d2.Operation();

学习示例：

    class Person
    {
        public Person()
        { }

        private string name;
        public Person(string name)
        {
            this.name = name;
        }

        public virtual void Show()
        {
            Console.WriteLine("装扮的{0}", name);
        }
    }

    class Finery : Person
    {
        protected Person component;

        //打扮
        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();
        }
    }

    class BigTrouser : Finery
    {
        public override void Show()
        {
            Console.Write("垮裤 ");
            base.Show();
        }
    }

    class Sneakers : Finery
    {
        public override void Show()
        {
            Console.Write("破球鞋 ");
            base.Show();
        }
    }

    class Suit : Finery
    {
        public override void Show()
        {
            Console.Write("西装 ");
            base.Show();
        }
    }

    class Tie : Finery
    {
        public override void Show()
        {
            Console.Write("领带 ");
            base.Show();
        }
    }

    class LeatherShoes : Finery
    {
        public override void Show()
        {
            Console.Write("皮鞋 ");
            base.Show();
        }
    }

客户端调用：

Person xc = new Person("小菜");

Console.WriteLine("\n第一种装扮：");

Sneakers pqx = new Sneakers();
BigTrouser kk = new BigTrouser();
TShirts dtx = new TShirts();

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

Console.WriteLine("\n第二种装扮：");

LeatherShoes px = new LeatherShoes();
Tie ld = new Tie();
Suit xz = new Suit();

px.Decorate(xc);
ld.Decorate(px);
xz.Decorate(ld);
xz.Show();

Console.WriteLine("\n第三种装扮：");
Sneakers pqx2 = new Sneakers();
LeatherShoes px2 = new LeatherShoes();
BigTrouser kk2 = new BigTrouser();
Tie ld2 = new Tie();

pqx2.Decorate(xc);
px2.Decorate(pqx);
kk2.Decorate(px2);
ld2.Decorate(kk2);

ld2.Show();