设计模式：Observer模式 之 互为观察者与被观察者

在现实世界中，没有单纯的观察者或者被观察者，大部分时候，一体两种角色兼备。

一个小小的实验：

namespace woodigg.DesignMode

{

    /// <summary>

    /// 通知对象

    /// </summary>

    public abstract class Human

    {

        /// <summary>

        /// 名字

        /// </summary>

        public string Name { get; set; }

        /// <summary>

        /// Constructor

        /// </summary>

        public Human(string name){

            this.Name = name;

        }             

        /// <summary>

        /// 委托

        /// </summary>

        /// <param name="name"></param>

        public delegate void HumanEventHandler(string name);       

        public event HumanEventHandler HumanEvent;

        /// <summary>

        /// 通知

        /// </summary>

        public virtual void Notify() {

            if (HumanEvent != null)

                HumanEvent(this.Name);

        } 

    }



    /// <summary>

    /// 观察者对象

    /// </summary>

    public abstract class Observer4Human : Human

    {

        /// <summary>

        /// 名字传递给基类

        /// </summary>

        /// <param name="name"></param>

        public Observer4Human(string name) : base(name) {}

        /// <summary>

        /// 通知回调方法

        /// </summary>

        /// <param name="name"></param>

        public abstract void Update(string name);

    }



    //--------------------- Concrete -------------------------//

    /// <summary>

    /// 丈夫

    /// </summary>

    public class Husband : Observer4Human 

    {

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



        public override void Notify()

        {

            Console.WriteLine(this.Name + " 喝多了!");

            base.Notify();

        }



        public override void Update(string name)

        {

            Console.WriteLine(this.Name + " 看着 "+name+" 不再闹了!");

        }

    }

    /// <summary>

    /// 妻子

    /// </summary>

    public class Wife : Observer4Human {

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



        public override void Update(string name)

        {

            Console.WriteLine(this.Name + " 被 "+name+" 吵醒了！");

            base.Notify();

        }

    }

    /// <summary>

    /// 孩子

    /// </summary>

    public class Baby : Observer4Human

    {

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



        public override void Update(string name)

        {

            Console.WriteLine(this.Name + " 被 "+name+" 吓哭了！");

            base.Notify();

        }

    }

}

测试代码：

[Test]

        public void HumanObserverTest()

        {

            //通知者

            Husband husband = new Husband("Johnny");



            Observer4Human wife = new Wife("Have");

            Observer4Human babe = new Baby("kitt");



            husband.HumanEvent +=new Human.HumanEventHandler(wife.Update);

            wife.HumanEvent += new Human.HumanEventHandler(babe.Update);

            babe.HumanEvent += new Human.HumanEventHandler(husband.Update);



            husband.Notify();

        }

NUnit结果：

 ***** woodigg.DesignMode.ObserverTest.AbstractObserverTest.HumanObserverTest
Johnny 喝多了!
Have 被 Johnny 吵醒了！
kitt 被 Have 吓哭了！
Johnny 看着 kitt 不再闹了!