装饰器模式

价值：在不改变对象原有行为的基础上，增加新的行为和属性。

装饰器模式 UML图：

代码如下：

 一、被装饰类

    #region 被装饰类
    public abstract class Person
    {
        public string name;
        public int age;
        public Person()
        {

        }
        public Person(string name,int age=20)
        {
            this.name = name;
            this.age = age;
        }

        public virtual void Show()
        {
            Console.WriteLine(string.Format("我的名字：{0},年龄：{1}",name,age));
        }
    }

    /// <summary>
    /// 白人子类
    /// </summary>
    public class WhitePerson : Person
    {
        public WhitePerson()
        {

        }
        public WhitePerson(string name)
            : base(name)
        {

        }
        public override void Show()
        {
            base.Show();
            Console.WriteLine(string.Format("肤色：{0}", "White"));
        }

    }
    #endregion

二、装饰类

    #region 装饰类
    /// <summary>
    /// 装饰类
    /// 1、继承Person，目的是在装饰A后的A1，将A1传递给B，再装饰为B1，不继承的话，无法将A1传递给B
    /// 2、引用Person的目的，是为了将A1当做参数传递给B，否则无法传递
    /// </summary>
    public abstract class Decorator:Person
    {
        protected Person person=null;
        public void Decorate(Person person)           
        {
            this.person = person;
        }

        public override void Show()
        {
            if(person!=null)
                person.Show();//此处是Person.Show(),而非 base.show()
        }
    }

    public class TShirtsDecorator : Decorator
    {
        public override void Show()
        {
            base.Show();     
            Console.Write(" TShirt ");
                              
        }
    }

    public class BigTrouseDecorator : Decorator
    {
        public override void Show()
        {
            base.Show();
            Console.Write(" BigTrouse ");
            
        }

    }

    public class SneakersDecorator : Decorator 
    {
        public override void Show()
        { 
            base.Show();
            Console.Write(" Sneakers ");
           
        }
    }
    #endregion

三、外部调用，进行装饰

 class Program
    {
        static void Main(string[] args)
        {
            //被装饰对象
            Person person = new WhitePerson("张三");

            //第一种装饰
            Console.WriteLine("第一种装饰：");
            TShirtsDecorator tShirts = new TShirtsDecorator();
            BigTrouseDecorator bigTrouse = new BigTrouseDecorator();
            SneakersDecorator sneakers = new SneakersDecorator();

            tShirts.Decorate(person);
            bigTrouse.Decorate(tShirts);//将tShirts当做参数，而非person
            sneakers.Decorate(bigTrouse);

            sneakers.Show();



            //第二种装饰
            Console.WriteLine("
第二种装饰：");

            TShirtsDecorator tShirts2 = new TShirtsDecorator();
            TShirtsDecorator tShirts22 = new TShirtsDecorator();
            BigTrouseDecorator bigTrouse2 = new BigTrouseDecorator();
            SneakersDecorator sneakers2 = new SneakersDecorator();


            tShirts2.Decorate(person);
            tShirts22.Decorate(tShirts2);
            bigTrouse2.Decorate(tShirts22);//将tShirts当做参数，而非person
            sneakers2.Decorate(bigTrouse2);

            sneakers2.Show();

            Console.Read();

        }
    }