C# Socket通讯连接多个客户端，判断是否掉线

创建服务器端Service

 1 public partial class Form1 : Form
 2     {
 3         public Form1()
 4         {
 5             InitializeComponent();
 6         }
 7         Socket socketsend;
 8         //创建负责监听的Socket
 9         Socket soceketWatch = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
10         Dictionary<string, Socket> dic_soceket = new Dictionary<string, Socket>();
11         private void button1_Click(object sender, EventArgs e)
12         {
13             //获得当前程序的ip地址
14             IPAddress addr = IPAddress.Parse(textBox1.Text);
15             //获得当前程序的端口号
16             IPEndPoint endpoint = new IPEndPoint(addr, int.Parse(textBox2.Text));
17             //服务器开启对当前程序的监听
18             soceketWatch.Bind(endpoint);
19             //创建监听队列,允许同时10个客户段排队
20             soceketWatch.Listen(10);
21             //显示监听信息
22             textBox3.AppendText("监听成功，等待客户端连接！" + "\r\n");
23             //开启线程。不停监听有没有客户端连接过来；
24             //Accept()方法内部是一个循环，不停监听有没有客户端连接过来，soceketWatch连接上客户端后，就返回一个用于通信的socketsend
25             //定义的soceketWatch:用于监听有没有客户端连接的socket
26             //定义的socketsend:用于和客户端通信的socket
27 
28             Task.Factory.StartNew(() =>
29            {
30                while (true)
31                {
32                    try
33                    {
34                        socketsend = soceketWatch.Accept();  //Accept是一个不停监听的循环
35                        this.Invoke(new Action(() => { textBox3.AppendText(socketsend.RemoteEndPoint.ToString() + "连接成功！" + "\r\n"); }));
36                        dic_soceket.Add(socketsend.RemoteEndPoint.ToString(), socketsend);
37                        //comboBox1中添加新连上的客户端
38                        this.Invoke(new Action(() =>
39                        {
40                            comboBox1.Items.Add(socketsend.RemoteEndPoint.ToString());
41 
42                        }));
43                        //开启线程，不停监听客户端发来的信息；
44                        //Receive()方法内部是一个循环，socketsend不停监听有没有消息发过来
45                        Thread.Sleep(5);
46                        Receive(socketsend);
47                    }
48                    catch (Exception ex)
49                    {
50                        MessageBox.Show(ex.ToString());
51                    }
52                }
53            });
54         }
55 
56         private void Receive(Socket socketsend)
57         {
58             Task.Factory.StartNew(() =>
59             {
60                 while (true)
61                 {
62                     try
63                     {
64                         if (socketsend.Poll(-1, SelectMode.SelectRead))   //判断socket是否掉线
65                         {
66                             byte[] buffer = new byte[1024 * 1024 * 5];
67                             int nRead = socketsend.Receive(buffer, SocketFlags.Peek);
68                             int r = socketsend.Receive(buffer);  //r代表实际接收到的有效字节数
69                             if (nRead == 0)
70                             {
71                                 this.Invoke(new Action(() =>
72                                 {
73                                     textBox3.AppendText(socketsend.RemoteEndPoint.ToString() + "掉线" + "\r\n");
74                                     comboBox1.Items.Remove(socketsend.RemoteEndPoint.ToString());
75                                     if (comboBox1.Items.Count == 0)
76                                     {
77                                         comboBox1.Text = "";
78                                     }
79                                 }));
80                                 return;
81                             }
82                             string s = Encoding.UTF8.GetString(buffer, 0, r);   //将接收的字节转换为字符串
83                             this.Invoke(new Action(() => { textBox3.AppendText(s + "\r\n"); }));
84                         }
85                     }
86                     catch (Exception)
87                     {
88                         throw;
89                     }
90                 }
91             });
92         }
93         private void button2_Click(object sender, EventArgs e)
94         {
95             //发送信号给客户端
96             byte[] buffer = Encoding.UTF8.GetBytes(textBox4.Text.Trim());
97             dic_soceket[comboBox1.SelectedItem.ToString()].Send(buffer);
98         }
99     }

View Code

创建客户端Client

 1  public partial class Form1 : Form
 2     {
 3         public Form1()
 4         {
 5             InitializeComponent();
 6         }
 7         Socket socketclient;
 8         private void button1_Click(object sender, EventArgs e)
 9         {
10             socketclient = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
11             IPAddress ip = IPAddress.Parse(textBox1.Text);
12             IPEndPoint port = new IPEndPoint(ip, int.Parse(textBox2.Text));
13             socketclient.Connect(port);
14             textBox3.AppendText(socketclient.RemoteEndPoint.ToString() + "连接成功！" + "\r\n");
15             Task.Factory.StartNew(() =>
16             {
17                 while(true)
18                 {
19                     try
20                     {
21                         byte[] buffer = new byte[1024 * 1024 * 5];
22                         int r = socketclient.Receive(buffer);
23                         if (r == 0)
24                         { return; }
25                         string s = Encoding.UTF8.GetString(buffer, 0, r);
26                         this.Invoke(new Action(() => { textBox3.AppendText(s + "\r\n"); }));
27                     }
28                     catch (Exception)
29                     {
30 
31                         throw;
32                     }
33                 }
34             });
35         }
36 
37         private void button2_Click(object sender, EventArgs e)
38         {
39             byte[] buffer = Encoding.UTF8.GetBytes(textBox4.Text.Trim());
40             socketclient.Send(buffer);
41         }
42     }

View Code

判断Socket是否掉线

 1 if (socketsend.Poll(-1, SelectMode.SelectRead))   //判断socket是否掉线，socketsend是和客户端通信的socket
 2                         {
 3                             byte[] buffer = new byte[1024 * 1024 * 5];
 4                             int nRead = socketsend.Receive(buffer, SocketFlags.Peek);   //
 5                             int r = socketsend.Receive(buffer);  //r代表实际接收到的有效字节数
 6                             if (nRead == 0)
 7                             {
 8                                 this.Invoke(new Action(() =>
 9                                 {
10                                     textBox3.AppendText("掉线" + "\r\n");
11                                 }));
12                                 return;
13                             }
14                             string s = Encoding.UTF8.GetString(buffer, 0, r);   //将接收的字节转换为字符串
15                             this.Invoke(new Action(() => { textBox3.AppendText(s + "\r\n"); }));  //输出收到的信息
16                         }