C# Socket编程实现简单的局域网聊天器的示例代码

public void StartListen()
{
 // 创建Socket对象 new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)
 Socket socket = GetSocket();
 // 将套接字与IPEndPoint绑定
 socket.Bind(this.GetIPEndPoint());
 // 开启监听 仅支持一个连接
 socket.Listen(1);
 // 开启线程等待客户端接入，避免堵塞
 Thread acceptThread = new Thread(new ThreadStart(TryAccept));
 acceptThread.IsBackground = true;
 acceptThread.Start();
}

public void TryAccept()
{
 Socket socket = GetSocket();
 while (true)
 {
  try
  {
   Socket connectedSocket = socket.Accept()
   this.ConnectedSocket = connectedSocket;
   OnConnect(); // 连接成功回调
   this.StartReceive(); // 开始接收线程
   break;
  }
  catch (Exception e)
  {
  }
 }
}

public void StartConnect()
{
 Thread connectThread = new Thread(new ThreadStart(TryConnect));
 connectThread.IsBackground = true;
 connectThread.Start();
}

public void TryConnect()
{
 Socket socket = GetSocket();
 while (true)
 {
  try
  {
   socket.Connect(this.GetIPEndPoint());
   this.ConnectedSocket = socket;
   OnConnect(); // 连接成功回调
   this.StartReceive();
   break;
  }
  catch (Exception e)
  {
   Thread.Sleep(TryConnectInterval); // 指定间隔后重新尝试连接
  }
 }
}

public bool Send(string msg)
{
 if (ConnectedSocket != null && ConnectedSocket.Connected)
 {
  byte[] buffer = UTF8.GetBytes(msg); 
  byte[] len = BitConverter.GetBytes((long)buffer.Length); 
  byte[] content = new byte[1 + len.Length + buffer.Length]; 
  content[0] = (byte)ChatType.Str; // 发送信息类型，字符串
  Array.Copy(len, 0, content, 1, len.Length); // 字符串字节长度
  Array.Copy(buffer, 0, content, 1 + len.Length, buffer.Length); // 实际字符串字节数据
  try
  {
   ConnectedSocket.Send(content);
   return true;
  }
  catch (Exception e)
  {
  }
 }
 return false;
}

public bool SendFile(string path)
{
 if (ConnectedSocket != null && ConnectedSocket.Connected)
 {
  try
  {
   FileInfo fi = new FileInfo(path);
   byte[] len = BitConverter.GetBytes(fi.Length); 
   byte[] name = UTF8.GetBytes(fi.Name); 
   byte[] nameLen = BitConverter.GetBytes(name.Length); 
   byte[] head = new byte[1 + len.Length + nameLen.Length + name.Length];
   head[0] = (byte)ChatType.File; // 加上信息发送类型
   Array.Copy(len, 0, head, 1, len.Length); // 加上文件长度
   Array.Copy(nameLen, 0, head, 1 + len.Length, nameLen.Length); // 加上文件名长度
   Array.Copy(name, 0, head, 1 + len.Length + nameLen.Length, name.Length); // 加上文件名字节数据
   ConnectedSocket.SendFile(
    path,
    head,
    null,
    TransmitFileOptions.UseDefaultWorkerThread
   );
   return true;
  }
  catch(Exception e)
  {
  }
 }
 return false;
}

public void Receive()
{
 if (ConnectedSocket != null)
 {
  while (true)
  {
   try
   {
    // 读取公共头部
    byte[] head = new byte[9];
    ConnectedSocket.Receive(head, head.Length, SocketFlags.None);
    int len = BitConverter.ToInt32(head, 1);
    if (head[0] == (byte) ChatType.Str)
    {
     // 接收字符串
     byte[] buffer = new byte[len];
     ConnectedSocket.Receive(buffer, len, SocketFlags.None);
     OnReceive(ChatType.Str, UTF8.GetString(buffer));
    }
    else if(head[0] == (byte)ChatType.File)
    {
     // 接收文件
     if (!Directory.Exists(dirName))
     {
      Directory.CreateDirectory(dirName);
     }
     // 读取文件名信息
     byte[] nameLen = new byte[4];
     ConnectedSocket.Receive(nameLen, nameLen.Length, SocketFlags.None);
     byte[] name = new byte[BitConverter.ToInt32(nameLen, 0)];
     ConnectedSocket.Receive(name, name.Length, SocketFlags.None);
     string fileName = UTF8.GetString(name);
     // 读取文件内容并写入
     int readByte = 0;
     int count = 0;
     byte[] buffer = new byte[1024 * 8];
     string filePath = Path.Combine(dirName, fileName);
     if (File.Exists(filePath))
     {
      File.Delete(filePath);
     }
     using (FileStream fs = new FileStream(filePath, FileMode.Append, FileAccess.Write))
     {
      while (count != len)
      {
       int readLength = buffer.Length;
       if(len - count < readLength)
       {
        readLength = len - count;
       }
       readByte = ConnectedSocket.Receive(buffer, readLength, SocketFlags.None);
       fs.Write(buffer, 0, readByte);
       count += readByte;
      }
     }
     OnReceive(ChatType.File, fileName); 
    }
    else
    {
     // 未知类型
    }
   }
   catch (Exception e)
   {
   }
  }
 }
}