Imports System.Text
Imports System.Net
Imports System.Net.Sockets
Imports System.Threading
 
Public Class Form1
 
    Dim hostsocket As New Socket(AddressFamily.InterNetwork, SocketType.Stream, _
      ProtocolType.IP)
 
    Dim clientsocket As Socket
 
    Public Shared serverstat As Integer = 0
 
    Dim ClientThreads As New List(Of Thread)
 
    Dim clients As New List(Of Socket)
 
    Dim AcceptThread As New Thread(AddressOf AcceptClients)
 
    Private Sub HostBN_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles HostBN.Click
 
        Dim iphost As IPHostEntry = Dns.Resolve(Dns.GetHostName())
 
        Dim ip As IPAddress = iphost.AddressList(0)
 
        Dim port As Integer = 26000
 
        Dim endpoint As New IPEndPoint(ip, port)
 
        hostsocket.Bind(endpoint)
 
        hostsocket.Listen(5)
 
        serverstat = 1
 
        ServerStatLB.Text += " " & serverstat
 
        AcceptThread.Start()
 
    End Sub
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
 
        CheckForIllegalCrossThreadCalls = False
 
    End Sub
 
    Public Sub ReceiveFromClients()
 
        Dim clientnew As Socket = clientsocket
 
        Try
 
            Do While serverstat = 1
 
                Dim buffer(clientnew.ReceiveBufferSize) As Byte
 
                clientnew.Receive(buffer)
 
                Dim message As String = GetMessage(Encoding.ASCII.GetString( _
                  buffer))
 
                MessTB.Text += message & Environment.NewLine
 
            Loop
 
        Catch ex As Exception
 
        End Try
 
    End Sub
 
    Private Sub AcceptClients()
 
        Do While serverstat = 1
 
            clientsocket = hostsocket.Accept()
 
            Dim bytes(clientsocket.ReceiveBufferSize) As Byte
 
            clientsocket.Receive(bytes)
 
            Dim message As String = GetMessage(Encoding.ASCII.GetString(bytes))
 
            If message.StartsWith("con") Then
 
                message = message.Remove(0, 3)
 
                ClientsLB.Items.Add(message)
 
                Dim responsemessage As String = message & " you are now" & _
                  "connected!"
 
                Dim rbytes() As Byte = Encoding.ASCII.GetBytes(responsemessage)
 
                clientsocket.Send(rbytes)
 
                clients.Add(clientsocket)
 
                Dim tmpClient As New Thread(AddressOf ReceiveFromClients)
 
                tmpClient.Start()
 
                ClientThreads.Add(tmpClient)
 
                Label1.Text = ClientThreads.Count
 
            End If
 
        Loop
 
    End Sub
 
    Public Shared Function GetMessage(ByVal Message As String) As String
 
        Dim mess As String = Nothing
 
        For i As Integer = 0 To Message.Length - 1
 
            If Message(i) = Nothing Then
 
                Exit For
 
            Else
 
                mess += Message(i)
 
            End If
 
        Next
 
        Return mess
 
    End Function
 
    Public Sub SetMessage(ByVal Message As String)
 
        Label2.Text += Message & Environment.NewLine
 
    End Sub
 
End Class