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