using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;
using System.Collections;

namespace WCFChatService
{
  // SessionMode.Required 允許Session會話。雙工協(xié)定時的回調(diào)協(xié)定類型為IChatCallback接口
  [ServiceContract(SessionMode = SessionMode.Required, CallbackContract = typeof(IChatCallback))]
  public interface IChatService
  {
    [OperationContract(IsOneWay = false, IsInitiating = true, IsTerminating = false)]//----->IsOneWay = false等待服務器完成對方法處理;IsInitiating = true啟動Session會話,IsTerminating = false 設置服務器發(fā)送回復后不關(guān)閉會話
    string[] Join(string name);//用戶加入

    [OperationContract(IsOneWay = true, IsInitiating = false, IsTerminating = false)]
    void Say(string msg);//群聊信息

    [OperationContract(IsOneWay = true, IsInitiating = false, IsTerminating = false)]
    void Whisper(string to, string msg);//私聊信息

    [OperationContract(IsOneWay = true, IsInitiating = false, IsTerminating = true)]
    void Leave();//用戶加入
  }
  /// <summary>
  /// 雙向通信的回調(diào)接口
  /// </summary>
  interface IChatCallback
  {
    [OperationContract(IsOneWay = true)]
    void Receive(string senderName, string message);

    [OperationContract(IsOneWay = true)]
    void ReceiveWhisper(string senderName, string message);

    [OperationContract(IsOneWay = true)]
    void UserEnter(string name);

    [OperationContract(IsOneWay = true)]
    void UserLeave(string name);
  }

  /// <summary>
  /// 設定消息的類型
  /// </summary>
  public enum MessageType { Receive, UserEnter, UserLeave, ReceiveWhisper };
  /// <summary>
  /// 定義一個本例的事件消息類. 創(chuàng)建包含有關(guān)事件的其他有用的信息的變量，只要派生自EventArgs即可。
  /// </summary>
  public class ChatEventArgs : EventArgs
  {
    public MessageType msgType;
    public string name;
    public string message;
  }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;

namespace WCFChatService
{
  // InstanceContextMode.PerSession 服務器為每個客戶會話創(chuàng)建一個新的上下文對象。ConcurrencyMode.Multiple 異步的多線程實例
  [ServiceBehavior(InstanceContextMode = InstanceContextMode.PerSession, ConcurrencyMode = ConcurrencyMode.Multiple)]
  public class ChatService : IChatService
  {
    private static Object syncObj = new Object();////定義一個靜態(tài)對象用于線程部份代碼塊的鎖定，用于lock操作
    IChatCallback callback = null;

    public delegate void ChatEventHandler(object sender, ChatEventArgs e);//定義用于把處理程序賦予給事件的委托。
    public static event ChatEventHandler ChatEvent;//定義事件
    static Dictionary<string, ChatEventHandler> chatters = new Dictionary<string, ChatEventHandler>();//創(chuàng)建一個靜態(tài)Dictionary（表示鍵和值）集合(字典)，用于記錄在線成員，Dictionary<(Of <(TKey, TValue>)>) 泛型類

    private string name;
    private ChatEventHandler myEventHandler = null;


    public string[] Join(string name)
    {
      bool userAdded = false;
      myEventHandler = new ChatEventHandler(MyEventHandler);//將MyEventHandler方法作為參數(shù)傳遞給委托

      lock (syncObj)//線程的同步性，同步訪問多個線程的任何變量，利用lock(獨占鎖)，確保數(shù)據(jù)訪問的唯一性。
      {
        if (!chatters.ContainsKey(name) && name != "" && name != null)
        {
          this.name = name;
          chatters.Add(name, MyEventHandler);
          userAdded = true;
        }
      }

      if (userAdded)
      {
        callback = OperationContext.Current.GetCallbackChannel<IChatCallback>();//獲取當前操作客戶端實例的通道給IChatCallback接口的實例callback,此通道是一個定義為IChatCallback類型的泛類型,通道的類型是事先服務契約協(xié)定好的雙工機制。
        ChatEventArgs e = new ChatEventArgs();//實例化事件消息類ChatEventArgs
        e.msgType = MessageType.UserEnter;
        e.name = name;
        BroadcastMessage(e);
        ChatEvent += myEventHandler;
        string[] list = new string[chatters.Count]; //以下代碼返回當前進入聊天室成員的稱列表
        lock (syncObj)
        {
          chatters.Keys.CopyTo(list, 0);//將字典中記錄的用戶信息復制到數(shù)組中返回。
        }
        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;//創(chuàng)建一個臨時委托實例
        lock (syncObj)
        {
          chatterTo = chatters[to]; //查找成員字典中，找到要接收者的委托調(diào)用
        }
        chatterTo.BeginInvoke(this, e, new AsyncCallback(EndAsync), null);//異步方式調(diào)用接收者的委托調(diào)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);
    }

    //回調(diào)，根據(jù)客戶端動作通知對應客戶端執(zhí)行對應的操作
    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)
      {
        //循環(huán)將在線的用戶廣播信息
        foreach (ChatEventHandler handler in temp.GetInvocationList())
        {
          //異步方式調(diào)用多路廣播委托的調(diào)用列表中的ChatEventHandler 
          handler.BeginInvoke(this, e, new AsyncCallback(EndAsync), null);
        }
      }
    }
    //廣播中線程調(diào)用完成的回調(diào)方法功能：清除異常多路廣播委托的調(diào)用列表中異常對象（空對象）
    private void EndAsync(IAsyncResult ar)
    {
      ChatEventHandler d = null;

      try
      {
        //封裝異步委托上的異步操作結(jié)果
        System.Runtime.Remoting.Messaging.AsyncResult asres = (System.Runtime.Remoting.Messaging.AsyncResult)ar;
        d = ((ChatEventHandler)asres.AsyncDelegate);
        d.EndInvoke(ar);
      }
      catch
      {
        ChatEvent -= d;
      }
    }
  }
}

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.ServiceModel;

namespace WCFChatClient
{
  public partial class ChatForm : Form, IChatServiceCallback
  {
    /// <summary>
    /// 該函數(shù)將指定的消息發(fā)送到一個或多個窗口。此函數(shù)為指定的窗口調(diào)用窗口程序，直到窗口程序處理完消息再返回。　
    /// </summary>
    /// <param name="hWnd">其窗口程序?qū)⒔邮障⒌拇翱诘木浔?lt;/param>
    /// <param name="msg">指定被發(fā)送的消息</param>
    /// <param name="wParam">指定附加的消息指定信息</param>
    /// <param name="lParam">指定附加的消息指定信息</param>
    [DllImport("user32.dll")]
    private static extern int SendMessage(IntPtr hWnd, int msg, int wParam, IntPtr lParam);
    //當一個窗口標準垂直滾動條產(chǎn)生一個滾動事件時發(fā)送此消息給那個窗口，也發(fā)送給擁有它的控件
    private const int WM_VSCROLL = 0x115;
    private const int SB_BOTTOM = 7;
    private int lastSelectedIndex = -1;

    private ChatServiceClient proxy;
    private string userName;

    private WaitForm wfDlg = new WaitForm();
    private delegate void HandleDelegate(string[] list);
    private delegate void HandleErrorDelegate();

    public ChatForm()
    {
      InitializeComponent();
      ShowInterChatMenuItem(true);
    }

    /// <summary>
    /// 連接服務器
    /// </summary>
    private void InterChatMenuItem_Click(object sender, EventArgs e)
    {
      lbOnlineUsers.Items.Clear();
      LoginForm loginDlg = new LoginForm();
      if (loginDlg.ShowDialog() == DialogResult.OK)
      {
        userName = loginDlg.txtUserName.Text;
        loginDlg.Close();
      }

      txtChatContent.Focus();
      Application.DoEvents();
      InstanceContext site = new InstanceContext(this);//為實現(xiàn)服務實例的對象進行初始化
      proxy = new ChatServiceClient(site);
      IAsyncResult iar = proxy.BeginJoin(userName, new AsyncCallback(OnEndJoin), null);
      wfDlg.ShowDialog();
    }

    private void OnEndJoin(IAsyncResult iar)
    {
      try
      {
        string[] list = proxy.EndJoin(iar);
        HandleEndJoin(list);

      }
      catch (Exception e)
      {
        HandleEndJoinError();
      }

    }
    /// <summary>
    /// 錯誤提示
    /// </summary>
    private void HandleEndJoinError()
    {
      if (wfDlg.InvokeRequired)
        wfDlg.Invoke(new HandleErrorDelegate(HandleEndJoinError));
      else
      {
        wfDlg.ShowError("無法連接聊天室!");
        ExitChatSession();
      }
    }
    /// <summary>
    /// 登錄結(jié)束后的處理
    /// </summary>
    /// <param name="list"></param>
    private void HandleEndJoin(string[] list)
    {
      if (wfDlg.InvokeRequired)
        wfDlg.Invoke(new HandleDelegate(HandleEndJoin), new object[] { list });
      else
      {
        wfDlg.Visible = false;
        ShowInterChatMenuItem(false);
        foreach (string name in list)
        {
          lbOnlineUsers.Items.Add(name);
        }
        AppendText(" 用戶: " + userName + "--------登錄---------" + DateTime.Now.ToString()+ Environment.NewLine);
      }
    }
    /// <summary>
    /// 退出聊天室
    /// </summary>
    private void OutInterChatMenuItem_Click(object sender, EventArgs e)
    {
      ExitChatSession();
      Application.Exit();
    }
    /// <summary>
    /// 群聊
    /// </summary>
    private void btnChat_Click(object sender, EventArgs e)
    {
      SayAndClear("", txtChatContent.Text, false);
      txtChatContent.Focus();
    }
    /// <summary>
    /// 發(fā)送消息
    /// </summary>
    private void SayAndClear(string to, string msg, bool pvt)
    {
      if (msg != "")
      {
        try
        {
          CommunicationState cs = proxy.State;
          //pvt 公聊還是私聊
          if (!pvt)
          {
            proxy.Say(msg);
          }
          else
          {
            proxy.Whisper(to, msg);
          }

          txtChatContent.Text = "";
        }
        catch
        {
          AbortProxyAndUpdateUI();
          AppendText("失去連接： " + DateTime.Now.ToString() + Environment.NewLine);
          ExitChatSession();
        }
      }
    }
    private void txtChatContent_KeyPress(object sender, KeyPressEventArgs e)
    {
      if (e.KeyChar == 13)
      {
        e.Handled = true;
        btnChat.PerformClick();
      }
    }
    /// <summary>
    /// 只有選擇一個用戶時，私聊按鈕才可用
    /// </summary>
    private void lbOnlineUsers_SelectedIndexChanged(object sender, EventArgs e)
    {
      AdjustWhisperButton();
    }
    /// <summary>
    /// 私聊
    /// </summary>    
    private void btnWhisper_Click(object sender, EventArgs e)
    {
      if (txtChatDetails.Text == "")
      {
        return;
      }
      object to = lbOnlineUsers.SelectedItem;
      if (to != null)
      {
        string receiverName = (string)to;
        AppendText("私下對" + receiverName + "說: " + txtChatContent.Text);//+ Environment.NewLine
        SayAndClear(receiverName, txtChatContent.Text, true);
        txtChatContent.Focus();
      }
    }
    /// <summary>
    /// 連接聊天室
    /// </summary>
    private void ShowInterChatMenuItem(bool show)
    {
      InterChatMenuItem.Enabled = show;
      OutInterChatMenuItem.Enabled = this.btnChat.Enabled = !show;
    }
    private void AppendText(string text)
    {
      txtChatDetails.Text += text;
      SendMessage(txtChatDetails.Handle, WM_VSCROLL, SB_BOTTOM, new IntPtr(0));
    }
    /// <summary>
    /// 退出應用程序時,釋放使用資源
    /// </summary>
    private void ExitChatSession()
    {
      try
      {
        proxy.Leave();
      }
      catch { }
      finally
      {
        AbortProxyAndUpdateUI();
      }
    }
    /// <summary>
    /// 釋放使用資源
    /// </summary>
    private void AbortProxyAndUpdateUI()
    {
      if (proxy != null)
      {
        proxy.Abort();
        proxy.Close();
        proxy = null;
      }
      ShowInterChatMenuItem(true);
    }
    /// <summary>
    /// 接收消息
    /// </summary>
    public void Receive(string senderName, string message)
    {
      AppendText(senderName + "說: " + message + Environment.NewLine);
    }
    /// <summary>
    /// 接收私聊消息
    /// </summary>
    public void ReceiveWhisper(string senderName, string message)
    {
      AppendText(senderName + " 私下說: " + message + Environment.NewLine);
    }
    /// <summary>
    /// 新用戶登錄
    /// </summary>
    public void UserEnter(string name)
    {
      AppendText("用戶 " + name + " --------登錄---------" + DateTime.Now.ToString() + Environment.NewLine);
      lbOnlineUsers.Items.Add(name);
    }
    /// <summary>
    /// 用戶離開
    /// </summary>
    public void UserLeave(string name)
    {
      AppendText("用戶 " + name + " --------離開---------" + DateTime.Now.ToString() + Environment.NewLine);
      lbOnlineUsers.Items.Remove(name);
      AdjustWhisperButton();
    }
    /// <summary>
    /// 控制私聊按鈕的可用性,只有選擇了用戶時按鈕才可用
    /// </summary>
    private void AdjustWhisperButton()
    {
      if (lbOnlineUsers.SelectedIndex == lastSelectedIndex)
      {
        lbOnlineUsers.SelectedIndex = -1;
        lastSelectedIndex = -1;
        btnWhisper.Enabled = false;
      }
      else
      {
        btnWhisper.Enabled = true;
        lastSelectedIndex = lbOnlineUsers.SelectedIndex;
      }

      txtChatContent.Focus();
    }
    /// <summary>
    /// 窗體關(guān)閉時，釋放使用資源
    /// </summary>
    private void ChatForm_FormClosed(object sender, FormClosedEventArgs e)
    {
      AbortProxyAndUpdateUI();
      Application.Exit();
    }
  }
}

if (host.Description.Behaviors.Find<System.ServiceModel.Description.ServiceMetadataBehavior>() == null)
      {
        BindingElement metaElement = new TcpTransportBindingElement();
        CustomBinding metaBind = new CustomBinding(metaElement);
        host.Description.Behaviors.Add(new System.ServiceModel.Description.ServiceMetadataBehavior());
        host.AddServiceEndpoint(typeof(System.ServiceModel.Description.IMetadataExchange), metaBind, "MEX");
      }