1. 服务端：
   
2. '用vb.net做一个简单的聊天工具，可以实现群发的
   
3. Imports System.Threading
   
4. Imports System.Net
   
5. Imports System.Net.Sockets
   
6. 
   
7. Public Class Form1
   
8. 
   
9.     Dim ListenSocket As New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp) '创建监听的套接字
   
10.     Dim Dict As New Dictionary(Of String, Socket) '用于保存连接的客户的套接字的键值对集合
    
11.     Dim DictThre As New Dictionary(Of String, Thread) '用于保存通信线程的键值对集合
    
12. 
    
13.     Private Sub ButListen_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ButListen.Click '开始监听的按钮
    
14.         TextBox.CheckForIllegalCrossThreadCalls = False '取消文本框的跨线程检查
    
15.         Dim Address As IPAddress = IPAddress.Parse(TxtIP.Text.Trim)
    
16.         Dim EndPoint As New IPEndPoint(Address, TxtPort.Text) '创建一个网络节点对象
    
17.         ListenSocket.Bind(EndPoint) '给负责监听的套接字绑定一个网络节点
    
18.         ListenSocket.Listen(2)
    
19.         ShowMsg("正在监听……")
    
20.         Dim thre As New Thread(AddressOf Connect) '创建一个新的线程用于处理客户端发来的连接请求
    
21.         thre.IsBackground = True '设为后台线程
    
22.         thre.Start() '开启线程
    
23.     End Sub
    
24. 
    
25.     Sub Connect() '处理客户端的连接请求的过程
    
26.         While True
    
27.             Dim SockConect As Socket = ListenSocket.Accept
    
28.             ShowMsg("连接成功！" & "（连接信息：" & SockConect.RemoteEndPoint.ToString & "）")
    
29.             Dict.Add(SockConect.RemoteEndPoint.ToString, SockConect) '将连接成功的套接字添加到键值对集合
    
30.             LBOnLine.Items.Add(SockConect.RemoteEndPoint.ToString) '添加到列表
    
31.             Dim Thre As New Thread(AddressOf RecClient) '创建一个新的线程用于和链接成功的套接字通信
    
32.             Thre.IsBackground = True '设为后台线程
    
33.             Thre.Start(SockConect)
    
34.             DictThre.Add(SockConect.RemoteEndPoint.ToString, Thre) '将创建的通信线程添加到键值对集合
    
35.         End While
    
36.     End Sub
    
37. 
    
38.     Sub RecClient(ByVal SockTelNet As Socket) '处理客户端发来的数据
    
39.         While True
    
40.             Dim AryMsg(1024) As Byte
    
41.             Dim RecLen As Int32
    
42. 
    
43.             Try '捕获异常
    
44.                 RecLen = SockTelNet.Receive(AryMsg) '接受客户端发来得信息
    
45.             Catch ss As SocketException
    
46.                 ShowMsg(ss.NativeErrorCode & vbCrLf & ss.Message) '显示错误信息
    
47.                 Dict.Remove(SockTelNet.RemoteEndPoint.ToString) '移除断开连接的套接字
    
48.                 LBOnLine.Items.Remove(SockTelNet.RemoteEndPoint.ToString) '从列表中移除
    
49.                 Return
    
50.             Catch s As Exception
    
51.                 ShowMsg(s.Message)
    
52.                 Return
    
53.             End Try
    
54. 
    
55.             Dim StrMsg As String
    
56.             StrMsg = System.Text.Encoding.UTF8.GetChars(AryMsg, 0, RecLen)
    
57.             ShowMsg("接收：" & StrMsg)
    
58.         End While
    
59.     End Sub
    
60. 
    
61.     Sub ShowMsg(ByVal Msg As String) '显示信息
    
62.         TxtMsg.AppendText(Format(DateTime.Now, "F") & vbCrLf & "   " & Msg & vbCrLf & vbCrLf) 'TxtMsg用途显示消息记录
    
63.     End Sub
    
64. 
    
65.     Sub SendMsg(ByVal Msg As String) '发送信息
    
66.         Dim AryMsg() = System.Text.Encoding.UTF8.GetBytes(Msg)
    
67.         Try '捕获异常
    
68.             Dict(LBOnLine.SelectedItem).Send(AryMsg) '给选中用户发送消息
    
69.         Catch ss As SocketException
    
70.             ShowMsg(ss.NativeErrorCode & vbCrLf & ss.Message)
    
71.             Return
    
72.         Catch s As Exception
    
73.             ShowMsg(s.Message)
    
74.             Return
    
75.         End Try
    
76.         ShowMsg("发送：" & Msg)
    
77.     End Sub
    
78. 
    
79.     Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click 'Button1发送消息的按钮
    
80.         SendMsg(TxtSendMsg.Text) '发送消息
    
81.     End Sub
    
82. 
    
83.     Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click 'Button2群发的按钮
    
84.         For Each a In Dict.Values '遍历通信套接字键值对集合，群发消息
    
85.             Dim AryMsg() = System.Text.Encoding.UTF8.GetBytes(TxtSendMsg.Text.Trim)
    
86.             Try '捕获异常
    
87.                 a.Send(AryMsg) '发送消息
    
88.             Catch ss As SocketException
    
89.                 ShowMsg(ss.NativeErrorCode & vbCrLf & ss.Message)
    
90.             Catch s As Exception
    
91.                 ShowMsg(s.Message)
    
92.             End Try
    
93.         Next
    
94.         ShowMsg("群发：" & TxtSendMsg.Text.Trim)
    
95.     End Sub
    
96. End Class
    
97. 客户端：
    
98. 客户端和服务端发送和接收数据的处理基本一样的，只是一个是主动连接的，一个是被动连接的
    
99. Imports System.Net
    
100. Imports System.Net.Sockets
     
101. Imports System.Threading
     
102. 
     
103. Public Class Form1
     
104.     Dim SockClient As New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp) '穿件一个
     
105. 
     
106.     Private Sub ButListen_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ButListen.Click
     
107.         TextBox.CheckForIllegalCrossThreadCalls = False '取消文本框的跨线程检查
     
108.         Dim Address As IPAddress = IPAddress.Parse(TxtIP.Text.Trim)
     
109.         Dim Endpoint As New IPEndPoint(Address, TxtPort.Text)
     
110.         Try '捕获异常
     
111.             SockClient.Connect(Endpoint) '发起连接
     
112.         Catch ss As SocketException
     
113.             ShowMsg(ss.Message)
     
114.             Return
     
115.         Catch s As Exception
     
116.             ShowMsg(s.Message)
     
117.             Return
     
118.         End Try
     
119. 
     
120.         ShowMsg("连接成功！")
     
121.         Dim Thre As New Thread(AddressOf RecMsg) '创建接收数据的线程
     
122.         Thre.IsBackground = True
     
123.         Thre.Start()
     
124.     End Sub
     
125. 
     
126.     Sub RecMsg() '接受数据处理
     
127.         While True
     
128.             Dim AryMsg(1024) As Byte
     
129.             Dim RecLen As Int32
     
130. 
     
131.             Try '捕获异常
     
132.                 RecLen = SockClient.Receive(AryMsg)
     
133.             Catch ss As SocketException
     
134.                 ShowMsg(ss.Message)
     
135.                 Return
     
136.             Catch s As Exception
     
137.                 ShowMsg(s.Message)
     
138.                 Return
     
139.             End Try
     
140. 
     
141.             Dim StrMsg As String
     
142.             StrMsg = System.Text.Encoding.UTF8.GetChars(AryMsg, 0, RecLen)
     
143.             ShowMsg("接收：" & StrMsg)
     
144.         End While
     
145.     End Sub
     
146. 
     
147.     Sub ShowMsg(ByVal Msg As String) '显示信息
     
148.         TxtMsg.AppendText(Format(DateTime.Now, "F") & vbCrLf & Msg & vbCrLf)
     
149.     End Sub
     
150. 
     
151.     Private Sub ButSendMsg_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ButSendMsg.Click
     
152.         SendMsg(TxtSendMsg.Text.Trim)
     
153.     End Sub
     
154. 
     
155.     Sub SendMsg(ByVal Msg As String) '发送数据
     
156.         Dim AryMsg() = System.Text.Encoding.UTF8.GetBytes(Msg)
     
157. 
     
158.         Try '捕获异常
     
159.             SockClient.Send(AryMsg)
     
160.         Catch ss As SocketException
     
161.             ShowMsg(ss.Message)
     
162.             Return
     
163.         Catch s As Exception
     
164.             ShowMsg(s.Message)
     
165.             Return
     
166.         End Try
     
167. 
     
168.         ShowMsg("发送：" & Msg)
     
169.     End Sub
     
170. End Class
     
171. 这个简单的例子就到这了
     

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