用 vb.net socket通信
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Dim th As Threading.Thread
2 Dim tcpl As System.Net.Sockets.TcpListener
3
4 Private Sub Form1_Load()Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
5 th = New System.Threading.Thread(New System.Threading.ThreadStart(AddressOf MyListen))
6 th.Start()
7 End Sub
8
9 Public Sub SendMessage()Sub SendMessage(ByVal IP As String, ByVal SendMsg As String)
10 Try
11 If IP "" Then
12 Dim tcpc As New System.Net.Sockets.TcpClient(IP, 5656)
13 Dim tcpStream As Net.Sockets.NetworkStream = tcpc.GetStream
14 Dim reqStream As New IO.StreamWriter(tcpStream)
15 reqStream.Write(SendMsg)
16 reqStream.Flush()
17 tcpStream.Close()
18 tcpc.Close()
19 End If
20 Catch ex As Exception
21 MsgBox(ex.Message.ToString)
22 End Try
23 End Sub
24 Private Sub MyListen()Sub MyListen()
25 Try
26 Dim ipAddress As System.Net.IPAddress = System.Net.Dns.Resolve(System.Net.Dns.GetHostName).AddressList(0)
27 tcpl = New System.Net.Sockets.TcpListener(ipAddress, 5656)
28 tcpl.Start()
29 While True
30 Dim s As System.Net.Sockets.Socket = tcpl.AcceptSocket()
31 Dim MyBuffer(1024) As Byte
32 Dim i As Integer
33 i = s.Receive(MyBuffer)
34 If i 0 Then
35 Dim lstrRec As String
36 Dim j As Integer
37 For j = 0 To i - 1
38 TextBox1.Text += Chr(MyBuffer(j)) ","
39 Next
40 End If
41 End While
42 Catch ex As Exception
43 MsgBox(ex.Message.ToString)
44 End Try
45 End Sub
46
47 Private Sub Button1_Click()Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
48 SendMessage("192.168.0.61", TextBox2.Text)
49 End Sub
与语言没有关系, 你需要考虑的是两个系统直接如何通讯. 选一种通讯协议(一般用http协议), 设计好数据结构, 可以是xml或json. 假设选用http协议传输json数据. 你需要做以下工作:
使用php开发一个http接口, 根据参数查询数据库, 把结果转换为json格式后返回. 这是目前最流行的接口格式, 基本上所有语言都可以开发和请求这样的接口, 很多开放平台都是这样设计接口的, 例如微信的这个接口,你可以参考一下 网页链接
使用VB.NET请求这个接口, 获取返回的数据(json格式, 一个特殊的字符串), 使用VB.NET对json数据进行解码
所以,要完成这个工作,你需要知道http接口开发和请求, 以及json编码和解码的相关知识和技能, 祝你好运
关于串口通讯的问题：
很明显，你还不知道（不会、不习惯）使用事件驱动的方式接收数据。
建议你仔细看看串口组件（无论VB6还是VB.net）的OnComm事件，你的问题很容易解决。
关于以太网通讯：
在TCP通讯中端口确实可以重用，你百度一下“TCP端口重用”能查到很多示例。
但绝大多数情况下不推荐端口重用，而应该采取服务器端建立连接池的方法。
或者，干脆不用TCP，用UDP解决也可以。
就可以了，我有一段不太成熟的代码：
Imports System.Net
Imports System.Net.Sockets
Imports System.Threading
Imports System.IO
Public Class Form1
Dim TCPListenerRun, TCPClientRun As Boolean
Dim ControlTCPClient, ServerClient As TcpClient
Dim ControlTCPListener As TcpListener
Dim TCPClientT, TCPListenerT As Thread
Private ControlStream, SControlStream As NetworkStream
Private ControlReadStream, SControlReadStream As StreamReader
Private ControlWriteStream, SControlWriteStream As StreamWriter
'异步委托
Private Delegate Sub InvokeDelegate(ByVal iMessage As String)
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Try
If TCPListenerRun Then
TCPListenerT.Abort()
ControlTCPListener.Stop()
TCPListenerRun = False
Button1.Text = "启动服务端 "
TextBox2.AppendText( "服务器已停止！ " vbCrLf)
Else
ControlTCPListener = New TcpListener(IPAddress.Parse( "127.0.0.1 "), 13000)
ControlTCPListener.Start()
TCPListenerT = New Thread(AddressOf Listen)
TCPListenerT.Start()
TextBox2.AppendText( "等待连接... " vbCrLf)
TextBox2.AppendText( "服务器已启动！ " vbCrLf)
TCPListenerRun = True
Button1.Text = "停止服务端 "
End If
Catch ex As Exception
TextBox2.AppendText(ex.Message vbCrLf)
End Try
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
Try
If TCPClientRun Then
TCPClientT.Abort()
ControlTCPClient.Close()
TCPClientRun = False
Button2.Text = "启动客户端 "
Else
ControlTCPClient = New TcpClient(New IPEndPoint(IPAddress.Parse( "127.0.0.1 "), 13001))
ControlTCPClient.Connect(New IPEndPoint(IPAddress.Parse( "127.0.0.1 "), 13000))
TCPClientRun = True
Button2.Text = "停止客户端 "
TCPClientT = New Thread(AddressOf Receive)
TCPClientT.Start()
ControlStream = ControlTCPClient.GetStream()
ControlReadStream = New StreamReader(ControlStream)
ControlWriteStream = New StreamWriter(ControlStream)
End If
Catch ex As SocketException
'If ex.ErrorCode = 10048 Then
ControlTCPClient.Close()
'End If
TCPClientRun = False
Button2.Text = "启动客户端 "
TextBox2.AppendText(ex.Message vbCrLf)
End Try
End Sub
Private Sub Listen()
ServerClient = ControlTCPListener.AcceptTcpClient
TextBox2.BeginInvoke(New InvokeDelegate(AddressOf InvokeMethod_Receive), "成功连接... ")
SControlStream = ServerClient.GetStream()
SControlReadStream = New StreamReader(SControlStream)
SControlWriteStream = New StreamWriter(SControlStream)
While True
TextBox2.BeginInvoke(New InvokeDelegate(AddressOf InvokeMethod_Receive), SControlReadStream.ReadLine())
End While
End Sub
Private Sub Receive()
While True
TextBox2.BeginInvoke(New InvokeDelegate(AddressOf InvokeMethod_Receive), ControlReadStream.ReadLine())
'Console.WriteLine(ControlTCPClient.Available)
End While
End Sub
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
TCPListenerRun = False
TCPClientRun = False
End Sub
Private Sub InvokeMethod_Receive(ByVal iMessage As String)
TextBox2.AppendText(iMessage vbCrLf)
End Sub
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
ControlWriteStream.WriteLine(TextBox1.Text)
ControlWriteStream.Flush()
End Sub
Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
SControlWriteStream.WriteLine(TextBox3.Text)
SControlWriteStream.Flush()
End Sub
End Class