装饰模式(Decorator Pattern)：

动态地给一个对象增加一些额外的职责，就增加对象功能来说，装饰模式比生成子类实现更为灵活。

模式角色与结构：

示例代码：

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace CSharp.DesignPattern.DecoratorPattern{    class Program    {        static void Main(string[] args)        {            Component component;            Component componentDecorator;            component = new Window();            componentDecorator = new ScrollBarDecorator(component);            componentDecorator.display();            component = new TextBox();            componentDecorator = new BlackBorderDecorator(component);            componentDecorator.display();            Console.ReadLine();        }    }    // 抽象构件    abstract class Component    {        public abstract void display();    }    // 具体构件    class Window : Component    {        public override void display()        {            Console.WriteLine("Window...");        }    }    class TextBox : Component    {        public override void display()        {            Console.WriteLine("TextBox...");        }    }    // 抽象装饰类    class ComponentDecorator : Component    {        private Component component; // 维持对抽象构件类型对象的引用        public ComponentDecorator(Component component) // 注入抽象构件类型的对象        {            this.component = component;        }        public override void display()        {            component.display();        }    }    // 具体装饰类    class ScrollBarDecorator : ComponentDecorator    {        public ScrollBarDecorator(Component component)             : base(component)        {           }        public override void display()        {            this.SetScrollBar();            base.display();        }        public void SetScrollBar()        {            Console.WriteLine("Add Scroll Bar...");        }    }    class BlackBorderDecorator : ComponentDecorator    {        public BlackBorderDecorator(Component component)            : base(component)        { }        public override void display()        {            this.SetBlackBorder();            base.display();        }        public void SetBlackBorder()        {            Console.WriteLine("Add Black Border...");        }    }}