EventClient.cs
using System;using System.Reflection;using System.Collections;using System.Threading;using System.Runtime.Remoting;using System.Runtime.Remoting.Channels.Http;using System.Runtime.Remoting.Channels;using System.Runtime.Serialization;using System.Runtime.Remoting.Activation;namespace SAF.EventNotification
{
/// <summary>
/// EventClient 部署在客戶端 /// 因爲需要與服務端通信，必須是可序列化的，所以繼承自 MarshalByRefObject
/// </summary> public class EventClient : MarshalByRefObject { public delegate void EventProcessingHandler(string eventName,object content); public delegate void RepeaterHandler(string eventName, object content); private EventServer es; // 事件.{方法} private Hashtable repeatDelegate= new Hashtable(); public EventClient(string url) { // 註冊一個雙向通信(端口號爲0)的信道 IDictionary props = new Hashtable(); props["port"] = 0; BinaryClientFormatterSinkProvider clientProvider = new BinaryClientFormatterSinkProvider(); HttpChannel channel = new HttpChannel(props, clientProvider,null); ChannelServices.RegisterChannel(channel); // 獲取遠程代理類，遠程類必須是Singleton類型的，才能保證獲取的是同一個對象的代理 es = (EventServer)Activator.GetObject(typeof(EventServer),url); } /// <summary> /// 增加一個方法的註冊 /// </summary> /// <param name="eventName">event name</param> /// <param name="s">delegate on the client side that process the event notification</param> public void SubscribeEvent(string eventName, EventProcessingHandler s) { try { // 檢查該事件是否已註冊過 Delegate handler =(Delegate)repeatDelegate[eventName]; // 如果事件註冊過，將新註冊的委託加入原有事件委託的列表中 Delegate.Combine(handler, s); // hashtable 的事件委託重新指向新委託鏈 if (handler != null) { //chain up the delegates together handler = Delegate.Combine(handler, s); //reset the delegate object in the hashtable repeatDelegate[eventName] = handler; } else { // 如果事件沒有註冊過，在hashtable中加入新的事件名及其委託 // 生成一個新的EventProcessingHandler委託 在服務端註冊 // 爲什麼使用新生成的委託對象註冊，而不用原有的委託來註冊？？ // 個人認爲是其它對象沒有與服務端通信的信道，只有EventClient註冊過這樣的信道。 // 順帶着的好處是服務端不用按照事件註冊的方法數發通知，只需按照事件註冊的客戶數發通知即可。 repeatDelegate.Add(eventName,s); EventClient.EventProcessingHandler repeat = new EventClient.EventProcessingHandler(Repeat); //subscribe the "repeat" delegate to the EventServer. es.SubscribeEvent(eventName,repeat); } } catch (Exception ex) { Console.WriteLine(ex.Message); } } /// <summary> /// 撤銷一個方法的註冊 /// </summary> /// <param name="eventName">event name</param> /// <param name="s">delegate on the client side that process the event notification</param> public void UnSubscribeEvent(string eventName, EventProcessingHandler s) { // 取出相關事件的委託鏈 Delegate handler =(Delegate)repeatDelegate[eventName]; // 如果委託不爲空，撤銷該方法的註冊 Delegate.Remove(handler, s); if (handler != null) { handler = Delegate.Remove(handler, s); //reassign the chain back to the hashtable. repeatDelegate[eventName] = handler; } } /// <summary> /// EventClient接到服務端的消息通知後的處理方法 /// </summary> /// <param name="eventName">event name</param> /// <param name="content">the content of the notification</param> public void Repeat(string eventName, object content) { // 從 hashtable 中取出事件的委託鏈 EventProcessingHandler eph = (EventProcessingHandler)repeatDelegate[eventName]; // 如果委託不爲空，向這些委託發送消息通知 if (eph !=null) { eph(eventName, content); } } /// <summary> /// 發佈一個事件的消息 /// </summary> /// <param name="eventName">event name</param> /// <param name="content">event content</param> public void RaiseEvent(string eventName, object content) { es.RaiseEvent(eventName,content); } }
}EventServer.cs
using System;using System.Collections;using SAF.EventNotification;namespace SAF.EventNotification{ /// <summary> /// EventServer 部署在服務端 /// </summary> public class EventServer : MarshalByRefObject { // 事件.{客戶} private Hashtable delegateMap =new Hashtable(); public EventServer() { } /// <summary> /// keep the EventServer live forever /// </summary> /// <returns></returns> public override object InitializeLifetimeService() { //object live indefinitely return null; } /// <summary> /// 註冊一個客戶端事件 /// 類型是 EventClient.EventProcessingHandler /// </summary> /// <param name="eventName">event name</param> /// <param name="handler">client side delegate</param> public void SubscribeEvent(string eventName, EventClient.EventProcessingHandler handler) { //ensure that only one thread modify the delegate chain at a time. lock(this) { Delegate delegateChain = (Delegate)delegateMap[eventName]; // 檢查事件是否註冊過，如果沒有註冊過加入hashtable即可 if (delegateChain == null) { delegateMap.Add(eventName,handler); } else { // 如果事件註冊過，將委託加入事件的委託鏈中 delegateChain = Delegate.Combine(delegateChain, handler); // 事件委託指向新委託鏈地址 delegateMap[eventName] = delegateChain; } } } /// <summary> /// 撤銷註冊 /// </summary> /// <param name="eventName">event name</param> /// <param name="handler"></param> public void UnSubscribeEvent(string eventName, EventClient.EventProcessingHandler handler) { //ensure that only one thread modify the delegate chain at a time. lock(this) { Delegate delegateChain = (Delegate)delegateMap[eventName]; // 事件委託存在的話，從委託鏈中刪除委託 if (delegateChain != null) { //remove the delegate from the chain delegateChain = Delegate.Remove(delegateChain,handler); // 將委託指針指向新的委託鏈 delegateMap[eventName] = delegateChain; } } } /// <summary> /// 發佈消息 /// </summary> /// <param name="eventName">event name</param> /// <param name="content">content of the notification</param> public void RaiseEvent(string eventName, object content) { Delegate delegateChain = (Delegate)delegateMap[eventName]; // 取得當前委託的鏈結構，不受後面的刪除操作影響 IEnumerator invocationEnumerator = delegateChain.GetInvocationList().GetEnumerator(); //loop through each delegate and invoke it. while(invocationEnumerator.MoveNext()) { Delegate handler = (Delegate)invocationEnumerator.Current; try { handler.DynamicInvoke(new object[]{eventName,content}); // 發佈消息 } catch (Exception ex) { // 產生異常時刪除當前委託，並且將事件委託鏈指向新委託鏈 delegateChain = Delegate.Remove(delegateChain, handler); delegateMap[eventName] = delegateChain; } } } }}