(精华)2020年10月21日 设计模式案例 事件总线实现原理

EventBus实现原理

#region { // 1、创建事件总线 EventBus eventBus = EventBus.Instance; TeacherEventListener teacherEventListener = new TeacherEventListener(); eventBus.AddListener(teacherEventListener); Teacher teacher = new Teacher(); TeacherSendNoticEvent teacherSendNoticEvent = new TeacherSendNoticEvent(teacher); // 2、发布事件 eventBus.PublishEvent(teacherSendNoticEvent); } #endregion

相关类

/// <summary> /// 事件总线 /// 广播事件 /// </summary> class EventBus { private EventBus() { } private static EventBus _eventBus = null; /// <summary> /// 初始化空的事件总件 /// </summary> public static EventBus Instance { get { return _eventBus ?? (_eventBus = new EventBus()); } } /// <summary> /// 监听器集合 /// </summary> private static ISet<IEventListener> eventListeners = new HashSet<IEventListener>(); /// <summary> /// 添加监听器(处理事件) /// </summary> /// <param name="eventListener"></param> public void AddListener(IEventListener eventListener) { eventListeners.Add(eventListener); } /// <summary> /// 移除监听器 /// </summary> public void RemoveListener(IEventListener eventListener) { eventListeners.Remove(eventListener); } /// <summary> /// 发布事件 /// </summary> public void PublishEvent(Event evnt) { if (evnt == null) throw new ArgumentNullException("evnt"); // 循环通知 foreach (var listener in eventListeners) { listener.OnEvent(evnt); } } } /// <summary> /// 事件 /// </summary> abstract class Event { // 事件源(就是对象) public object source { get; } protected Event(object source) { this.source = source; } } /// <summary> /// 事件监听器(处理事件) /// </summary> interface IEventListener { /// <summary> /// 事件处理 /// </summary> /// <param name="event"></param> void OnEvent(Event @event); } /// <summary> /// 数据库连接关系事件 /// </summary> class ConnectionCloseEvent : Event { public ConnectionCloseEvent(object source) : base(source) { } } /// <summary> /// Connection监听器 /// </summary> class ConnectionListener : IEventListener { public void OnEvent(Event @event) { Console.WriteLine("事件被触发了"); } } /// <summary> /// 老师发送通告事件 /// </summary> class TeacherEventListener : IEventListener { public void OnEvent(Event @event) { throw new NotImplementedException(); } } /// <summary> /// 老师发送通告事件 /// </summary> class TeacherSendNoticEvent : Event { public TeacherSendNoticEvent(object source) : base(source) { } }