wcf客户间通信

悄悄话的功能其实是不难实现的， 看完下面的代码你就知道怎么做。

  // InstanceContextMode.PerSession 服务器为每个客户会话创建一个新的上下文对象。ConcurrencyMode.Multiple 异步的多线程实例
  [ServiceBehavior(InstanceContextMode = InstanceContextMode.PerSession, ConcurrencyMode = ConcurrencyMode.Multiple)]
  public class ChatService : IChatService
  {
  private static Object syncObj = new Object();////定义一个静态对象用于线程部份代码块的锁定，用于lock操作
  IChatCallback callback = null;

  public delegate void ChatEventHandler(object sender, ChatEventArgs e);//定义用于把处理程序赋予给事件的委托。
  public static event ChatEventHandler ChatEvent;//定义事件
  static Dictionary<string, ChatEventHandler> chatters = new Dictionary<string, ChatEventHandler>();//创建一个静态Dictionary（表示键和值）集合(字典)，用于记录在线成员，Dictionary<(Of <(TKey, TValue>)>) 泛型类

  private string name;
  private ChatEventHandler myEventHandler = null;


  public string[] Join(string name)
  {
  bool userAdded = false;
  myEventHandler = new ChatEventHandler(MyEventHandler);//将MyEventHandler方法作为参数传递给委托

  lock (syncObj)//线程的同步性，同步访问多个线程的任何变量，利用lock(独占锁)，确保数据访问的唯一性。
  {
  if (!chatters.ContainsKey(name) && name != "" && name != null)
  {
  this.name = name;
  chatters.Add(name, MyEventHandler);
  userAdded = true;
  }
  }

  if (userAdded)
  {
  callback = OperationContext.Current.GetCallbackChannel<IChatCallback>();//获取当前操作客户端实例的通道给IChatCallback接口的实例callback,此通道是一个定义为IChatCallback类型的泛类型,通道的类型是事先服务契约协定好的双工机制。
  ChatEventArgs e = new ChatEventArgs();//实例化事件消息类ChatEventArgs
  e.msgType = MessageType.UserEnter;
  e.name = name;
  BroadcastMessage(e);
  ChatEvent += myEventHandler;
  string[] list = new string[chatters.Count]; //以下代码返回当前进入聊天室成员的称列表
  lock (syncObj)
  {
  chatters.Keys.CopyTo(list, 0);//将字典中记录的用户信息复制到数组中返回。
  }
  return list;
  }
  else
  {
  return null;
  }
  }

  public void Say(string msg)
  {
  ChatEventArgs e = new ChatEventArgs();
  e.msgType = MessageType.Receive;
  e.name = this.name;
  e.message = msg;
  BroadcastMessage(e);
  }

  public void Whisper(string to, string msg)
  {
  ChatEventArgs e = new ChatEventArgs();
  e.msgType = MessageType.ReceiveWhisper;
  e.name = this.name;
  e.message = msg;
  try
  {
  ChatEventHandler chatterTo;//创建一个临时委托实例
  lock (syncObj)
  {
  chatterTo = chatters[to]; //查找成员字典中，找到要接收者的委托调用
  }
  chatterTo.BeginInvoke(this, e, new AsyncCallback(EndAsync), null);//异步方式调用接收者的委托调用
  }
  catch (KeyNotFoundException)
  {
  }
  }

  public void Leave()
  {
  if (this.name == null)
  return;

  lock (syncObj)
  {
  chatters.Remove(this.name);
  }
  ChatEvent -= myEventHandler;
  ChatEventArgs e = new ChatEventArgs();
  e.msgType = MessageType.UserLeave;
  e.name = this.name;
  this.name = null;
  BroadcastMessage(e);
  }

  //回调，根据客户端动作通知对应客户端执行对应的操作
  private void MyEventHandler(object sender, ChatEventArgs e)
  {
  try
  {
  switch (e.msgType)
  {
  case MessageType.Receive:
  callback.Receive(e.name, e.message);
  break;
  case MessageType.ReceiveWhisper:
  callback.ReceiveWhisper(e.name, e.message);
  break;
  case MessageType.UserEnter:
  callback.UserEnter(e.name);
  break;
  case MessageType.UserLeave:
  callback.UserLeave(e.name);
  break;
  }
  }
  catch
  {
  Leave();
  }
  }

  private void BroadcastMessage(ChatEventArgs e)
  {

  ChatEventHandler temp = ChatEvent;

  if (temp != null)
  {
  //循环将在线的用户广播信息
  foreach (ChatEventHandler handler in temp.GetInvocationList())
  {
  //异步方式调用多路广播委托的调用列表中的ChatEventHandler 
  handler.BeginInvoke(this, e, new AsyncCallback(EndAsync), null);
  }
  }
  }
  //广播中线程调用完成的回调方法功能：清除异常多路广播委托的调用列表中异常对象（空对象）
  private void EndAsync(IAsyncResult ar)
  {
  ChatEventHandler d = null;

  try
  {
  //封装异步委托上的异步操作结果
  System.Runtime.Remoting.Messaging.AsyncResult asres = (System.Runtime.Remoting.Messaging.AsyncResult)ar;
  d = ((ChatEventHandler)asres.AsyncDelegate);
  d.EndInvoke(ar);
  }
  catch
  {
  ChatEvent -= d;
  }
  }
  }