C#聊天程序服务端与客户端完整实例代码

本文所述为基于C#实现的多人聊天程序服务端与客户端完整代码。本实例省略了结构定义部分，服务端主要是逻辑处理部分代码，因此使用时需要完善一些窗体按钮之类的。

先看服务端代码如下：

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Net;
using System.Net.Sockets;
using System.Threading;
namespace 多人聊天程序Server端
{
 /// <summary>
 /// 应用程序的主入口点。
 /// </summary>
 [STAThread]
 static void Main()
 {
  Application.Run(new Form1());
 }
 // 启动服务按钮
 private void button2_Click(object sender, System.EventArgs e)
 {
  try
  {
  // 必须填写端口
  if(txtPort.Text == "")
  {
   MessageBox.Show("请先填写服务端口号!", "提示");
   return;
  }
  Int32 port = Int32.Parse(txtPort.Text); // 获得端口号
  // 创建侦听的Socket
  mainSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
  IPEndPoint localEP = new IPEndPoint(IPAddress.Any, port);
  // 将 Socket 绑定到本地的终结点上
  mainSocket.Bind(localEP);
  // 开始侦听，最大的连接数是 5
  mainSocket.Listen(5);
  // 开始一个异步操作接受客户的连接请求
  mainSocket.BeginAccept(new AsyncCallback(OnClientConnect), null);
  // 启动服务按钮不可用，停止服务按钮可用
  UpdateControls(true);
  }
  catch(SocketException se)
  {
  MessageBox.Show(se.Message, "提示");
  }
 }
 // 更新“启动服务按钮”和“停止服务”按钮的状态：是否可用；
 // 注意：两个按钮的状态是互斥的
 private void UpdateControls(bool onServe)
 {
  button2.Enabled = !onServe;
  button3.Enabled = onServe;
  if(onServe)
  {
  status.Text = "已启动服务";
  }
  else
  {
  status.Text = "未启动服务";
  }
 }
 // 回调函数，当客户连接上时，将会被调用
 public void OnClientConnect(IAsyncResult asyn)
 {
  try
  {
  // 调用EndAccept完成BeginAccept异步调用，返回一个新的Socket处理与客户的通信
  Socket workerSocket = mainSocket.EndAccept(asyn);
  // 增加客户数目
  Interlocked.Increment(ref clientNum);
  // 将 workerSocket Socket加入到 ArrayList 中
  workerSocketList.Add(workerSocket);
  // 发送欢迎信息给连接上服务器的客户
  string msg = "欢迎客户 " + clientNum + " 登录服务器\n";
  SendWelcomeToClient(msg, clientNum);
  // 在线客户数目改变，必须更新客户列表
  UpdateClientListControl();
  // 连接上的客户接收数据
  WaitForData(workerSocket, clientNum);
  // 主 Socket 返回，继续等待其它的连接请求
  mainSocket.BeginAccept(new AsyncCallback(OnClientConnect), null);
  }
  catch(ObjectDisposedException)
  {
  System.Diagnostics.Debugger.Log(0,"1","\n OnClientConnection: Socket已经关闭!\n");
  }
  catch(SocketException se)
  {
  MessageBox.Show(se.Message, "提示");
  }
 }
 // 发送欢迎信息给客户
 void SendWelcomeToClient(string msg, int clientNumber)
 {
  // 用UTF8格式来将string信息转化成byte数组形式
  byte[] byData = System.Text.Encoding.UTF8.GetBytes(msg);
  // 获得客户clientNumber对应的Socket
  Socket workerSocket = (Socket)workerSocketList[clientNumber - 1];
  // 将数据发给客户
  workerSocket.Send(byData);
 }
 // 该类保存当前的socket，它的客户号还有发送给服务器的数据
 public class SocketPacket
 {
  public System.Net.Sockets.Socket currentSocket; // 当前的Socket
  public int clientNumber; // 客户号
  public byte[] dataBuffer = new byte[1024]; // 发给服务器的数据
  // 构造函数
  public SocketPacket(System.Net.Sockets.Socket socket, int clientNumber)
  {
  currentSocket = socket;
  this.clientNumber = clientNumber;
  }
 }
 // 开始等待客户发送数据
 public void WaitForData(System.Net.Sockets.Socket socket, int clientNumber)
 {
  try
  {
  if(pfnWorkerCallBack == null)
  {
   // 当连接上的客户有写的操作的时候，调用回调函数
   pfnWorkerCallBack = new AsyncCallback(OnDataReceived);
  }
  SocketPacket socketPacket = new SocketPacket(socket, clientNumber);
  socket.BeginReceive(socketPacket.dataBuffer, 0, socketPacket.dataBuffer.Length,
            SocketFlags.None, pfnWorkerCallBack, socketPacket);
  }
  catch(SocketException se)
  {
  MessageBox.Show (se.Message, "提示");
  }
 }
 // 当客户写数据时，调用以下方法
 public void OnDataReceived(IAsyncResult asyn)
 {
  SocketPacket socketData = (SocketPacket)asyn.AsyncState ;
  try
  {
  // EndReceive完成BeginReceive异步调用，返回客户写入流的字节数
  int iRx = socketData.currentSocket.EndReceive(asyn);
  // 加 1 是因为字符串以 '\0' 作为结束标志符
  char[] chars = new char[iRx + 1];
  // 对客户发来的信息进行UTF8解码，存入chars字符数组中
  System.Text.Decoder decoder = System.Text.Encoding.UTF8.GetDecoder();
  int charLen = decoder.GetChars(socketData.dataBuffer, 0, iRx, chars, 0);
  System.String szData = new System.String(chars);
  string msg = "客户 " + socketData.clientNumber + " 发的信息:" + szData;
  // 将客户发的数据加入到信息列表中
  AppendToRichEditControl(msg);
  // 等待数据
  WaitForData(socketData.currentSocket, socketData.clientNumber);
  }
  catch (ObjectDisposedException )
  {
  System.Diagnostics.Debugger.Log(0,"1","\nOnDataReceived: Socket已经关闭!\n");
  }
  catch(SocketException se)
  {
  if(se.ErrorCode == 10054)
  {
   // 将客户断开连接的信息写入信息列表中
   string msg = "客户 " + socketData.clientNumber + " 已断开了连接!" + "\n";
   AppendToRichEditControl(msg);
   // 移走已关闭的socket
   workerSocketList[socketData.clientNumber - 1] = null;
   // 更新客户列表
   UpdateClientListControl();
  }
  else
  {
   MessageBox.Show (se.Message, "提示");
  }
  }
 }
 // 更新信息列表，该方法可由主线程或其他工作线程所调用
 private void AppendToRichEditControl(string msg)
 {
  // 测试看是哪个线程调用了该方法
  if (InvokeRequired)
  {
  // We cannot update the GUI on this thread.
  // All GUI controls are to be updated by the main (GUI) thread.
  // Hence we will use the invoke method on the control which will
  // be called when the Main thread is free
  // Do UI update on UI thread
  object[] pList = {msg};
  txtRecvMsg.BeginInvoke(new UpdateRichEditCallback(OnUpdateRichEdit), pList);
  }
  else
  {
  // 创建该控件的主线程直接更新信息列表
  OnUpdateRichEdit(msg);
  }
 }
 // 添加信息到 txtRecvMsg 中
 private void OnUpdateRichEdit(string msg)
 {
 // txtRecvMsg.AppendText(msg);
  txtRecvMsg.Text = txtRecvMsg.Text + msg;
 }
 // 更新客户列表
 private void UpdateClientListControl()
 {
  if (InvokeRequired) // Is this called from a thread other than the one created
  // the control
  {
  clientList.BeginInvoke(new UpdateClientListCallback(UpdateClientList), null);
  }
  else
  {
  // 创建该控件的主线程直接更新信息列表
  UpdateClientList();
  }
 }
 // 更新客户列表
 void UpdateClientList()
 {
  clientList.Items.Clear(); // 清空客户列表
  for(int i = 0; i < workerSocketList.Count; i++)
  {
  // 加1，是因为数组从下标0开始，而我们的客户标号是从1开始
  string clientKey = Convert.ToString(i + 1);
  Socket workerSocket = (Socket)workerSocketList[i];
  if(workerSocket != null)
  {
   // 将连接着服务器的客户添加到客户列表中
   if(workerSocket.Connected)
   {
   clientList.Items.Add(clientKey);
   }
  }
  }
 }
 // 停止服务按钮
 private void button3_Click(object sender, System.EventArgs e)
 {
  CloseSockets();
  UpdateControls(false);
  // 更新客户列表
  UpdateClientListControl();
 }
 // 发送信息按钮
 private void button1_Click(object sender, System.EventArgs e)
 {
  // 如果在线客户列表不为空，则允许发送信息
  if (clientList.Items.Count != 0 )
  {
  try
  {
   string msg = txtSendMsg.Text;
   msg = "服务器信息: " + msg + "\n";
   byte[] byData = System.Text.Encoding.UTF8.GetBytes(msg);
   Socket workerSocket = null;
   for(int i = 0; i < workerSocketList.Count; i++)
   {
   workerSocket = (Socket)workerSocketList[i];
   if(workerSocket!= null)
   {
    // 发给所有连接上服务器的客户
    if(workerSocket.Connected)
    {
    workerSocket.Send(byData);
    }
   }
   }
  }
  catch(SocketException se)
  {
   MessageBox.Show(se.Message, "提示");
  }
  }
  else
  {
  MessageBox.Show("没有在线客户,不能发送信息!", "提示");
  }
 }
 // 清空信息按钮
 private void button4_Click(object sender, System.EventArgs e)
 {
  txtRecvMsg.Clear(); // 清空从客户发来的信息
 }
 // 关闭窗体按钮
 private void button5_Click(object sender, System.EventArgs e)
 {
  CloseSockets();
  Close();
 }
 // 关闭Socket
 void CloseSockets()
 {
  // 关闭主Socket
  if(mainSocket != null)
  {
  mainSocket.Close();
  }
  Socket workerSocket = null;
  // 关闭客户 Socket 数组
  for(int i = 0; i < workerSocketList.Count; i++)
  {
  workerSocket = (Socket)workerSocketList[i];
  if(workerSocket != null)
  {
   workerSocket.Close();
   workerSocket = null;
  }
  }
 }
 private void Form1_Load(object sender, System.EventArgs e)
 {
  try
  {
  // 获得本机的IP地址
  txtIP.Text = Dns.Resolve(Dns.GetHostName()).AddressList[0].ToString();
  // 启动时，启动服务按钮可用，停止服务按钮不可用
  UpdateControls(false);
  }
  catch(Exception exc)
  {
  MessageBox.Show(exc.Message, "提示");
  }
 }
 }
}

客户端主要实现接收来自服务端返回的消息、实现发送消息的操作界面，创建Socket实例，得到服务器的IP地址，更新控件，连接和断开等，具体代码如下：

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Net;
using System.Net.Sockets;
namespace 多人聊天程序Client端
{
 public class Form1 : System.Windows.Forms.Form
 {
 private System.Windows.Forms.Label label1;
 private System.Windows.Forms.TextBox txtIP;
 private System.Windows.Forms.Label label2;
 private System.Windows.Forms.Label label3;
 private System.Windows.Forms.RichTextBox txtSendMsg;
 private System.Windows.Forms.Label label4;
 private System.Windows.Forms.Button button1;
 private System.Windows.Forms.Button button2;
 private System.Windows.Forms.Button button3;
 private System.Windows.Forms.Button button4;
 private System.Windows.Forms.RichTextBox txtRecvMsg;
 private System.Windows.Forms.TextBox txtPort;
 private System.Windows.Forms.Button button5;
 private System.ComponentModel.Container components = null;
 byte[] m_dataBuffer = new byte[10];
 IAsyncResult result;
 public AsyncCallback pfnCallBack ;
 private System.Windows.Forms.Label status;
 private System.Windows.Forms.Label label5;
 public Socket clientSocket;
 public Form1()
 {
  InitializeComponent();
 }
 private void InitializeComponent()
 {
  this.label1 = new System.Windows.Forms.Label();
  this.txtIP = new System.Windows.Forms.TextBox();
  this.label2 = new System.Windows.Forms.Label();
  this.txtPort = new System.Windows.Forms.TextBox();
  this.label3 = new System.Windows.Forms.Label();
  this.txtSendMsg = new System.Windows.Forms.RichTextBox();
  this.label4 = new System.Windows.Forms.Label();
  this.status = new System.Windows.Forms.Label();
  this.txtRecvMsg = new System.Windows.Forms.RichTextBox();
  this.button1 = new System.Windows.Forms.Button();
  this.button2 = new System.Windows.Forms.Button();
  this.button3 = new System.Windows.Forms.Button();
  this.button4 = new System.Windows.Forms.Button();
  this.label5 = new System.Windows.Forms.Label();
  this.button5 = new System.Windows.Forms.Button();
  this.SuspendLayout();
  // label1
  this.label1.AutoSize = true;
  this.label1.Location = new System.Drawing.Point(16, 24);
  this.label1.Name = "label1";
  this.label1.Size = new System.Drawing.Size(60, 17);
  this.label1.TabIndex = 0;
  this.label1.Text = "服务器IP:";
  // txtIP
  this.txtIP.Location = new System.Drawing.Point(80, 24);
  this.txtIP.Name = "txtIP";
  this.txtIP.Size = new System.Drawing.Size(160, 21);
  this.txtIP.TabIndex = 1;
  this.txtIP.Text = "";
  // label2
  this.label2.AutoSize = true;
  this.label2.Location = new System.Drawing.Point(16, 56);
  this.label2.Name = "label2";
  this.label2.Size = new System.Drawing.Size(35, 17);
  this.label2.TabIndex = 2;
  this.label2.Text = "端口:";
  // txtPort
  this.txtPort.Location = new System.Drawing.Point(80, 56);
  this.txtPort.Name = "txtPort";
  this.txtPort.Size = new System.Drawing.Size(40, 21);
  this.txtPort.TabIndex = 3;
  this.txtPort.Text = "";
  // label3
  this.label3.AutoSize = true;
  this.label3.Location = new System.Drawing.Point(16, 96);
  this.label3.Name = "label3";
  this.label3.Size = new System.Drawing.Size(110, 17);
  this.label3.TabIndex = 4;
  this.label3.Text = "发送信息给服务器:";
  // txtSendMsg
  this.txtSendMsg.Location = new System.Drawing.Point(16, 120);
  this.txtSendMsg.Name = "txtSendMsg";
  this.txtSendMsg.Size = new System.Drawing.Size(224, 88);
  this.txtSendMsg.TabIndex = 5;
  this.txtSendMsg.Text = "";
  // label4
  this.label4.AutoSize = true;
  this.label4.Location = new System.Drawing.Point(16, 248);
  this.label4.Name = "label4";
  this.label4.Size = new System.Drawing.Size(60, 17);
  this.label4.TabIndex = 6;
  this.label4.Text = "连接状态:";
  // status
  this.status.Location = new System.Drawing.Point(80, 248);
  this.status.Name = "status";
  this.status.Size = new System.Drawing.Size(192, 23);
  this.status.TabIndex = 7;
  // txtRecvMsg
  this.txtRecvMsg.Location = new System.Drawing.Point(264, 80);
  this.txtRecvMsg.Name = "txtRecvMsg";
  this.txtRecvMsg.ReadOnly = true;
  this.txtRecvMsg.Size = new System.Drawing.Size(224, 144);
  this.txtRecvMsg.TabIndex = 8;
  this.txtRecvMsg.Text = "";
  // button1
  this.button1.Location = new System.Drawing.Point(280, 16);
  this.button1.Name = "button1";
  this.button1.Size = new System.Drawing.Size(88, 32);
  this.button1.TabIndex = 9;
  this.button1.Text = "连接";
  this.button1.Click += new System.EventHandler(this.button1_Click);
  // button2
  this.button2.Location = new System.Drawing.Point(384, 16);
  this.button2.Name = "button2";
  this.button2.Size = new System.Drawing.Size(88, 32);
  this.button2.TabIndex = 10;
  this.button2.Text = "断开";
  this.button2.Click += new System.EventHandler(this.button2_Click);
  // button3
  this.button3.Location = new System.Drawing.Point(280, 232);
  this.button3.Name = "button3";
  this.button3.Size = new System.Drawing.Size(88, 32);
  this.button3.TabIndex = 11;
  this.button3.Text = "清空信息";
  this.button3.Click += new System.EventHandler(this.button3_Click);
  // button4
  this.button4.Location = new System.Drawing.Point(384, 232);
  this.button4.Name = "button4";
  this.button4.Size = new System.Drawing.Size(88, 32);
  this.button4.TabIndex = 12;
  this.button4.Text = "关闭";
  this.button4.Click += new System.EventHandler(this.button4_Click);
  // label5
  this.label5.AutoSize = true;
  this.label5.Location = new System.Drawing.Point(264, 64);
  this.label5.Name = "label5";
  this.label5.Size = new System.Drawing.Size(134, 17);
  this.label5.TabIndex = 13;
  this.label5.Text = "收到服务器发来的信息:";
  // button5
  this.button5.Location = new System.Drawing.Point(16, 208);
  this.button5.Name = "button5";
  this.button5.Size = new System.Drawing.Size(224, 32);
  this.button5.TabIndex = 14;
  this.button5.Text = "发送信息";
  this.button5.Click += new System.EventHandler(this.button5_Click);
  // Form1
  this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);
  this.ClientSize = new System.Drawing.Size(512, 277);
  this.Controls.Add(this.button5);
  this.Controls.Add(this.label5);
  this.Controls.Add(this.button4);
  this.Controls.Add(this.button3);
  this.Controls.Add(this.button2);
  this.Controls.Add(this.button1);
  this.Controls.Add(this.txtRecvMsg);
  this.Controls.Add(this.status);
  this.Controls.Add(this.label4);
  this.Controls.Add(this.txtSendMsg);
  this.Controls.Add(this.label3);
  this.Controls.Add(this.txtPort);
  this.Controls.Add(this.label2);
  this.Controls.Add(this.txtIP);
  this.Controls.Add(this.label1);
  this.Name = "Form1";
  this.Text = "多人聊天程序Client端";
  this.Load += new System.EventHandler(this.Form1_Load);
  this.ResumeLayout(false);
 }
 #endregion
 [STAThread]
 static void Main()
 {
  Application.Run(new Form1());
 }
 // 连接按钮
 private void button1_Click(object sender, System.EventArgs e)
 {
  // IP地址和端口号不能为空
  if(txtIP.Text == "" || txtPort.Text == "")
  {
  MessageBox.Show("请先完整填写服务器IP地址和端口号!", "提示");
  return;
  }
  try
  {
  // 创建Socket实例
  clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
  // 得到服务器的IP地址
  IPAddress ipAddress = IPAddress.Parse(txtIP.Text);
  Int32 port = Int32.Parse(txtPort.Text);
  // 创建远程终结点
  IPEndPoint remoteEP = new IPEndPoint(ipAddress, port);
  // 连接到远程服务器
  clientSocket.Connect(remoteEP);
  if(clientSocket.Connected)
  {
   UpdateControls(true);
   WaitForData(); // 异步等待数据
  }
  }
  catch(SocketException se)
  {
  MessageBox.Show (se.Message, "提示");
  UpdateControls(false);
  }
 }
 // 等待数据
 public void WaitForData()
 {
  try
  {
  if(pfnCallBack == null)
  {
   // 当连接上的客户有写的操作的时候，调用回调函数
   pfnCallBack = new AsyncCallback(OnDataReceived);
  }
  SocketPacket socketPacket = new SocketPacket();
  socketPacket.thisSocket = clientSocket;
  result = clientSocket.BeginReceive(socketPacket.dataBuffer, 0, socketPacket.dataBuffer.Length,
   SocketFlags.None, pfnCallBack, socketPacket);
  }
  catch(SocketException se)
  {
  MessageBox.Show(se.Message, "提示");
  }
 }
 // 该类保存Socket以及发送给服务器的数据
 public class SocketPacket
 {
  public System.Net.Sockets.Socket thisSocket;
  public byte[] dataBuffer = new byte[1024]; // 发给服务器的数据
 }
 // 接收数据
 public void OnDataReceived(IAsyncResult asyn)
 {
  try
  {
  SocketPacket theSockId = (SocketPacket)asyn.AsyncState ;
  // EndReceive完成BeginReceive异步调用，返回服务器写入流的字节数
  int iRx = theSockId.thisSocket.EndReceive(asyn);
  // 加 1 是因为字符串以 '\0' 作为结束标志符
  char[] chars = new char[iRx + 1];
  // 用UTF8格式来将string信息转化成byte数组形式
  System.Text.Decoder decoder = System.Text.Encoding.UTF8.GetDecoder();
  int charLen = decoder.GetChars(theSockId.dataBuffer, 0, iRx, chars, 0);
  System.String szData = new System.String(chars);
  // 将收到的信息显示在信息列表中
  txtRecvMsg.Text = txtRecvMsg.Text + szData;
  // 等待数据
  WaitForData();
  }
  catch (ObjectDisposedException)
  {
  System.Diagnostics.Debugger.Log(0,"1","\nOnDataReceived: Socket已经关闭!\n");
  }
  catch(SocketException se)
  {
  if(se.ErrorCode == 10054)
  {
   string msg = "服务器" + "停止服务!" + "\n";
   txtRecvMsg.Text = txtRecvMsg.Text + msg;
   clientSocket.Close();
   clientSocket = null;
   UpdateControls(false);
  }
  else
  {
   MessageBox.Show(se.Message, "提示");
  }
  }
 }
 // 更新控件。连接和断开（发送信息）按钮的状态是互斥的
 private void UpdateControls(bool connected)
 {
  button1.Enabled = !connected;
  button2.Enabled = connected;
  button5.Enabled = connected;
  if(connected)
  {
  status.Text = "已连接";
  }
  else
  {
  status.Text = "无连接";
  }
 }
 // 断开按钮
 private void button2_Click(object sender, System.EventArgs e)
 {
  // 关闭Socket
  if(clientSocket != null)
  {
  clientSocket.Close();
  clientSocket = null;
  UpdateControls(false);
  }
 }
 // 发送信息按钮
 private void button5_Click(object sender, System.EventArgs e)
 {
  try
  {
  // 如果客户与服务器有连接，则允许发送信息
  if(clientSocket.Connected)
  {
   string msg = txtSendMsg.Text + "\n";
   // 用UTF8格式来将string信息转化成byte数组形式
   byte[] byData = System.Text.Encoding.UTF8.GetBytes(msg);
   if(clientSocket != null)
   {
   // 发送数据
   clientSocket.Send(byData);
   }
  }
  }
  catch(Exception se)
  {
  MessageBox.Show(se.Message, "提示");
  }
 }
 // 清空按钮
 private void button3_Click(object sender, System.EventArgs e)
 {
  txtRecvMsg.Clear(); // 清空信息列表
 }
 // 关闭按钮
 private void button4_Click(object sender, System.EventArgs e)
 {
  // 关闭Socket
  if(clientSocket != null)
  {
  clientSocket.Close();
  clientSocket = null;
  }
  Close(); // 关闭窗体
 }
 private void Form1_Load(object sender, System.EventArgs e)
 {
  UpdateControls(false); // 初始化时，只有连接按钮可用
 }
 }
}