C# TCP退出Accept阻塞的两种方法

方法一：将侦听套接字强行关掉，这样会使Accept引发异常，从而达到退出阻塞的目的。

方法二：先拆除循环条件，再给监听端口发送一条自定义命令，解析成功后，Accept自然退出阻塞。

后台代码：

[csharp] view plain copy

print?

1. using System;  
2. using System.Text;  
3. using System.Windows;  
4. using System.Threading;  
5. using System.Net;  
6. using System.Net.Sockets;  
7.   
8. namespace SocketBlockingInterrupt  
9. {  
10.     public partial class MainWindow : Window  
11.     {  
12.         bool bIsExecute;  
13.         TcpListener listener;//监听套接字  
14.         SynchronizationContext synContext;  
15.   
16.         public MainWindow()  
17.         {  
18.             InitializeComponent();  
19.             synContext = SynchronizationContext.Current;  
20.             btnStop.IsEnabled = false;  
21.         }  
22.   
23.         private void btnStart_Click(object sender, RoutedEventArgs e)  
24.         {  
25.             bIsExecute = true; //建立循环条件  
26.             btnStart.IsEnabled = false;  
27.             btnStop.IsEnabled = true;  
28.   
29.             //开启监听线程  
30.             Thread t = new Thread(new ThreadStart(ListenThread));  
31.             t.IsBackground = true;  
32.             t.Start();  
33.         }  
34.   
35.         void ListenThread()  
36.         {  
37.             IPEndPoint localEP = new IPEndPoint(IPAddress.Any, 9000);  
38.             listener = new TcpListener(localEP);  
39.             listener.Start();         //启动监听，非阻塞  
40.   
41.             synContext.Post(updateUI, "监听线程：正在监听中...");  
42.   
43.             while (bIsExecute) //循环条件  
44.             {  
45.                 byte[] recvBuff = new byte[512];  
46.   
47.                 //捕获异常，强行退出Accept阻塞  
48.                 try  
49.                 {  
50.                     synContext.Post(updateUI, "监听线程：Accept正在阻塞中...");  
51.   
52.                     TcpClient client = listener.AcceptTcpClient();     // 等待连接（阻塞）  
53.                     synContext.Post(updateUI, "监听线程：收到连接请求，已退出Accept阻塞");  
54.   
55.                     int recvByte = client.Client.Receive(recvBuff);// 建立连接  
56.   
57.                     // 解析命令  
58.                     byte[] buff = new byte[recvByte];  
59.                     for (int i = 0; i < recvByte; i++ ) { buff[i] = recvBuff[i]; }  
60.                     string exitByt = Encoding.ASCII.GetString(buff);  
61.                     if (exitByt == "Exit")  
62.                     {  
63.                         synContext.Post(updateUI, "监听线程：收到数据" + exitByt);  
64.                         break;  
65.                     }  
66.                 }  
67.                 catch (SocketException ex)  
68.                 {  
69.                     synContext.Post(updateUI, "监听线程：发生异常，Accept阻塞被强行退出：" + ex.Message);  
70.                     break;  
71.                 }  
72.             }  
73.             synContext.Post(updateUI, "监听线程：已成功退出监听");  
74.         }  
75.   
76.         private void btnStop_Click(object sender, RoutedEventArgs e)  
77.         {  
78.             bIsExecute = false; //此处拆除循环条件  
79.   
80.             //方法1：直接停止监听套接字，引发异常从而强行使Accept退出阻塞。  
81.             //---------------------------------------------  
82.             //if (listener != null)  
83.             //{  
84.             //    listener.Stop();  
85.             //}  
86.             //---------------------------------------------  
87.   
88.               
89.             //方法2：主动发送一条数据，使Accept自然地退出阻塞。  
90.             //---------------------------------------------  
91.             TcpClient tcpClient = new TcpClient();  
92.             tcpClient.Connect("127.0.0.1",9000);  
93.   
94.             NetworkStream ns = tcpClient.GetStream();  
95.             if (ns.CanWrite)  
96.             {  
97.                 Byte[] sendBytes = Encoding.ASCII.GetBytes("Exit");  
98.                 ns.Write(sendBytes, 0, sendBytes.Length);  
99.                 lbMsg.Items.Add("发送退出命令成功！");  
100.             }  
101.             else  
102.             {  
103.                 lbMsg.Items.Add("发送退出命令失败！");  
104.                 return;  
105.             }  
106.             ns.Close();  
107.             tcpClient.Close();  
108.             //---------------------------------------------  
109.   
110.             btnStart.IsEnabled = true;  
111.             btnStop.IsEnabled = false;  
112.         }  
113.   
114.         void updateUI(object o)  
115.         {  
116.             string str = (string)o;  
117.             lbMsg.Items.Add(str);  
118.         }  
119.     }  
120. }  

WPF前台代码：

[csharp] view plain copy

print?

1. <Window x:Class="SocketBlockingInterrupt.MainWindow"  
2.         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"  
3.         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"  
4.         Title="MainWindow" Height="350" Width="525">  
5.     <Grid>  
6.         <Button Content="开始侦听" Height="23" HorizontalAlignment="Left" Margin="12,12,0,0" Name="btnStart" VerticalAlignment="Top" Width="75" Click="btnStart_Click" />  
7.         <Button Content="结束侦听" Height="23" HorizontalAlignment="Left" Margin="108,12,0,0" Name="btnStop" VerticalAlignment="Top" Width="75" Click="btnStop_Click" />  
8.         <ListBox Height="258" HorizontalAlignment="Left" Margin="12,41,0,0" Name="lbMsg" VerticalAlignment="Top" Width="479" />  
9.     </Grid>  
10. </Window>