UML:

Component:定义一个对象接口,可以给这些对象动态的添加职责

ContreteComponent:定义了一个具体的对象,也可以给这个对象添加一些职责

Decorator:装饰抽象类,继承了Component,从外类来扩展Component类的功能,但对于Component来说,是无需知道Decrator的存在的

ContreteDecoratorA和ContreteDecoratorB都是具体的装饰对象,骑到给Component添加职责的功能

 

SAMPLE:

Component.cs

 

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

 

ConcreteComponent.cs

 

1     class ConcreteComponent:Component
2     {
3         public override void Operation()
4         {
5             Console.WriteLine("具体对象的操作");
6         }
7     }

 

Decorator.cs
 1     abstract class Decorator:Component
 2     {
 3         protected Component component;
 4         public void setComponent(Component component)
 5         {
 6             this.component = component;
 7         }
 8         public override void Operation()
 9         {
10             if (component != null)
11                 component.Operation();
12         }
13     }

 

ConcreteDecoratorA.cs
 1     class ConcreteDecoratorA : Decorator
 2     {
 3         private string addedState;
 4         public override void Operation()
 5         {
 6             base.Operation();
 7             addedState = "new state";
 8             Console.WriteLine("具体装饰对象A的操作");
 9         }
10     }

 

ConcreteDecoratorB.cs
 1     class ConcreteDecoratorB:Decorator
 2     {
 3         public override void Operation()
 4         {
 5             base.Operation();
 6             addMethod();
 7             Console.WriteLine("具体装饰对象B的操作");
 8         }
 9         //用来区别A方法
10         private void addMethod()
11         { }
12     }

 

Program.cs
1             ConcreteComponent c = new ConcreteComponent();
2             ConcreteDecoratorA d1 = new ConcreteDecoratorA();
3             ConcreteDecoratorB d2 = new ConcreteDecoratorB();
4 
5             d1.setComponent(c);
6             d2.setComponent(d2);
7             d2.Operation();

 

装饰模式是利用setComponent来对付对象进行包装的.这样每个装饰独享的实现就和如何使用这个对象分离开了,每个装饰对象只关心自己的功能,不需要关心如何被添加到对象链当中.