观察者模式（observer行为型）c#简单例子

几个要点：模式使目标与观察都之间的依赖关系达到松耦合、通知会自动传播

例子：玩家击中敌人后发生一系列变化：发后爆炸、敌人少1个....

namespace adapterpattern
{
    public partial class ObserverForm : Form
    {
        public ObserverForm()
        {
            InitializeComponent();
        }

        private void btnDisplay_Click(object sender, EventArgs e)
        {
            BaseData.EnemyNumber = 100;
            IObserver explosionEvent = new ExplosionEvent();
            IObserver enemy = new Enemy();
            player p1 = new player1();
            p1.AddObserver(explosionEvent);
            p1.AddObserver(enemy);
            p1.Notify();
            listBox1.Items.Add(p1.Display());
        }
    }
    public static class BaseData//数据中转站
    {
        public static string DisplayString { get; set; }
        public static int EnemyNumber { get; set; }
    }
    public abstract class player
    {
        List<IObserver> observers = new List<IObserver>();//观察员列表
        public virtual void Notify()
        {
            foreach (IObserver observer in observers)
            {
                observer.Update();//遂个通知观察员
            }
        }
        public virtual void AddObserver(IObserver observer)//增加观察员
        {
            observers.Add(observer);
        }
        public virtual void Delet(IObserver observer)//删除观察员
        {
            observers.Remove(observer);
        }
        public abstract string Display();
    }
    public class player1 : player
    {
        public override string Display()
        {
            return BaseData.DisplayString + BaseData.EnemyNumber.ToString();
        }
    }
    public interface IObserver//观察员接口
    {
        void Update();
    }
    public class ExplosionEvent : IObserver //观察员1
    {


        public void Update()
        {
            BaseData.DisplayString = "显示爆炸";
        }
    }
    public class Enemy : IObserver //观察员2
    {

        public void Update()
        {
            BaseData.EnemyNumber -= 1;       //"敌人数减少1个"; 
        }
    }
}

观察者模式（observer行为型）c#简单例子