老师视频里写聊天室那段，关于线程的。 - 黑马程序员技术交流社区

public Form1()
{
InitializeComponent();
TextBox.CheckForIllegalCrossThreadCalls = false;
}
Socket socketWatch;
Dictionary<string, Socket> dict = new Dictionary<string, Socket>();
bool flag = false;
private void btnBegin_Click(object sender, EventArgs e)
{
//创建负责监听的套接字，参数（使用IP4寻址协议，使用流式连接，使用TCP协议传输数据）
socketWatch = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
//获得文本框中的IP地址对象
IPAddress adress = IPAddress.Parse(txtIP.Text.Trim());
//创建包含ip和端口的网络节点对象
IPEndPoint endpoint = new IPEndPoint(adress, int.Parse(txtPORT.Text.Trim()));
//将负责监听的套接字绑定到唯一IP和端口上
socketWatch.Bind(endpoint);
// 设置监听队列的长度
socketWatch.Listen(10);
//创建负责监听的线程，并传入监听的方法
Thread watch = new Thread(ConnectionThd);
watch.IsBackground = true;
watch.Start();//开启线程
ShowMsg("启动成功");
if (flag)
{
Thread RecMsgthd = new Thread(RecMsg);
RecMsgthd.IsBackground = true;
RecMsgthd.Start(sokConnection);
}
}
Socket sokConnection;
/// <summary>
/// 监听客户端请求的方法
/// </summary>
void ConnectionThd()
{
while (true)
{
//开始监听客户端请求，注意Accpeet，会阻断当前进程
sokConnection = socketWatch.Accept();//一旦监听到客户端请求，就返回和客户端通信的套接字
//想列表控件中添加一个客户端的IP端口字符串，作为客户端的唯一标识
lbOnline.Items.Add(sokConnection.RemoteEndPoint.ToString());
//将与客户端通信的套接字对象sokConnection 添加到键值对集合中，并以客户端IP端口作为键
dict.Add(sokConnection.RemoteEndPoint.ToString(), sokConnection);
//Thread thdRec = new Thread(RecMsg);
//thdRec.IsBackground = true;
//thdRec.Start(sokConnection);
flag = true;
ShowMsg("客户端连接成功");
}
}
void ShowMsg(string msg)
{
txtMsg.AppendText(msg + "\n");
}
void RecMsg(object socketClientPara)
{
Socket socketClient = socketClientPara as Socket;
while (true)
{
//第一个接受用的缓存区（2M）
byte[] arrMsgRec = new byte[1024 * 1024 * 2];
int length = socketClient.Receive(arrMsgRec);
string strMsgRec = System.Text.Encoding.UTF8.GetString(arrMsgRec, 0, length);
ShowMsg(sokConnection.RemoteEndPoint.ToString() + "发送了数据：" + strMsgRec);
}
}
private void btnSend_Click(object sender, EventArgs e)
{
string strMsg = txtSend.Text.Trim();
byte[] arrMsg = System.Text.Encoding.UTF8.GetBytes(strMsg);
//获取列表中选中的key
string ClientKey = lbOnline.Text;
//通过key，找到字典集合中对应的与某客户通信的套接字的send方法，发送数据给对方
dict[ClientKey].Send(arrMsg);
//sokConnection.Send(arrMsg);
ShowMsg("发送了数据" + strMsg);
}

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