Imports
Imports
Imports System.Threading
Imports System.Text


Public Class Form1
    Dim Sserver As Socket = Nothing
    Dim newthread As Thread
    Dim newsocket As Socket
    Dim bytes(1024) As Byte
    Dim ii As Integer = 0

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        newthread = New Thread(AddressOf WaitData)
        newthread.Start()
        Button1.Enabled = False
        Button2.Enabled = True
    End Sub

    Public Sub WaitData()
        Sserver = New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)
        Dim ip_addr As IPAddress = IPAddress.Parse(TextBox1.Text)
        Dim localEP As New IPEndPoint(ip_addr, 502)
        Sserver.Bind(localEP)
        Sserver.Listen(100)
        While (True)
            Dim i As Integer
            newsocket = Sserver.Accept()

            i = newsocket.Receive(bytes)
            Dim str As String
            str = ""
            If i > 0 Then
                Dim j As Integer
                For j = 0 To i - 1
                    str += CStr(bytes(j))
                Next
            End If
            TextBox2.Text = str & ",  ii=" & ii & ", i=" & i
            ii += 1
            ' newsocket.Close()
        End While
    End Sub

    Public Sub New()
        ' 此调用是 Windows 窗体设计器所必需的。
        InitializeComponent()
        System.Windows.Forms.Control.CheckForIllegalCrossThreadCalls = False
        ' 在 InitializeComponent() 调用之后添加任何初始化。
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Sserver.Close()
        newthread.Abort()
        newsocket.Close()
        Button1.Enabled = True
        Button2.Enabled = False
        TextBox2.Text = ""
    End Sub
End Class

找了段之前在网上保存的代码，你看看对比一下吧 我测试没啥问题

Imports Imports Imports System.Text
Imports System.Threading


Public Class Form1
    Dim s As Socket = Nothing
    Dim t As Thread

    Public Sub WaitData()
        Dim serverAddress As String = ipText.Text()
        s = New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)  '使用TCP协议
        Dim localEndPoint As New IPEndPoint(IPAddress.Parse(serverAddress), 1024)        '指定IP和Port
        s.Bind(localEndPoint)                                                            '绑定到该Socket
        s.Listen(100)                                                                    '侦听，最多接受100个连接
        While (True)
            Dim bytes(1024) As Byte                                                      '用来存储接收到的字节
            Dim ss As Socket = s.Accept()                                                '若接收到,则创建一个新的Socket与之连接
            ss.Receive(bytes)                                                            '接收数据，若用ss.send(Byte()),则发送数据
            ListBox1.Items.Insert(0, Encoding.Unicode.GetString(bytes))                  '将其插入到列表框的第一项之前,若使用Encoding.ASCII.GetString(bytes),则接收到的中文字符不能正常显示
        End While
    End Sub

    Private Sub BtnStart_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnStart.Click
        t = New Thread(AddressOf WaitData)  '建立新的线程
        t.Start()                           '启动线程
        BtnStart.Enabled = False            '按钮不可用，避免另启线程
    End Sub

    Private Sub BtnStop_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnStop.Click
        Try
            s.Close()                     '关闭Socket
            t.Abort()                     '中止线程
        Catch
        Finally
            BtnStart.Enabled = True       '启用BtnStart
        End Try
    End Sub

    Private Sub Form1_closed(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Closed
        Try
            s.Close()
            t.Abort()
        Catch
        End Try
    End Sub
End Class

算了 把客户端代码也发给你看下

Imports Imports Imports System.Text



Public Class Form1
    Private Sub BtnSend_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnSend.Click
        Dim serverAddress As String = ipText.Text()
        Try
            Dim bytes(1024) As Byte
            Dim s = New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)
            Dim localEndPoint As New IPEndPoint(IPAddress.Parse(serverAddress), 1024)
            s.Connect(localEndPoint)
            s.Send(Encoding.Unicode.GetBytes(TextBox1.Text))
            s.Close()
        Catch ex As Exception
        End Try
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    End Sub
End Class

s.close
你每次发送完都close了
其实我我也是新手，关于通讯这块懂得很少