Imports System.Net
Imports System.Net.Sockets
Imports System.Threading
Public Class Form1
Private mPort As Integer
Private mListenerThread As Thread = Nothing
Private mClients As New List(Of ConnectedClient)
Public Delegate Sub ReceiveDelegate(ByRef c As ConnectedClient, ByVal s As String)
Private Sub ButtonStartStop_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ButtonStartStop.Click
If mListenerThread Is Nothing Then
Integer.TryParse(TextBoxPort.Text, mPort)
mListenerThread = New Thread(AddressOf ListenerFunction)
mListenerThread.Start(mPort)
Else
For Each Client As ConnectedClient In mClients
Client.Close()
Next
mClients.Clear()
mListenerThread.Abort()
mListenerThread.Join()
mListenerThread = Nothing
End If
End Sub
Private Sub ListenerFunction(ByVal Parameter As Object)
Dim Listener As TcpListener = Nothing
Try
Listener = New TcpListener(New IPAddress(New Byte() {127, 0, 0, 1}), mPort)
Listener.Start()
While True
While Listener.Pending
Dim Client As TcpClient = Listener.AcceptTcpClient()
mClients.Add(New ConnectedClient(Client, AddressOf Receive))
End While
Thread.Sleep(100)
End While
Catch ex As ThreadAbortException
Catch ex As Exception
Debug.Print("TcpListener Error:" + Environment.NewLine + ex.ToString)
Finally
If Listener IsNot Nothing Then
Listener.Stop()
End If
End Try
End Sub
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
Dim Client As ConnectedClient
If mListenerThread IsNot Nothing Then
If mListenerThread.IsAlive() Then
LabelStatus.Text = "Listening on Port " + mPort.ToString
Else
LabelStatus.Text = "Stopped."
End If
Else
LabelStatus.Text = "Stopped."
End If
ListBoxClients.Items.Clear()
For Each Client In mClients
If Client.Connected Then
ListBoxClients.Items.Add(Client)
End If
Next
Dim removeClient As ConnectedClient = Nothing
Do
removeClient = Nothing
For Each Client In mClients
If Not Client.Connected Then
removeClient = Client
Exit For
End If
Next
If removeClient IsNot Nothing Then
removeClient.Close()
mClients.Remove(removeClient)
Debug.Print("Removed Client from List - Timer")
End If
Loop While removeClient IsNot Nothing
removeClient = Nothing
End Sub
Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
mClients.Clear()
If mListenerThread IsNot Nothing Then
mListenerThread.Abort()
mListenerThread.Join()
End If
End Sub
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
End Sub
Private Sub Receive(ByRef c As ConnectedClient, ByVal s As String)
If RichTextBoxHistory.InvokeRequired Then
Dim d As New ReceiveDelegate(AddressOf Receive)
RichTextBoxHistory.Invoke(d, New Object() {c, s})
Else
RichTextBoxHistory.AppendText(c.RemoteHost + ": " + c.RemotePort.ToString + " : " + s)
RichTextBoxHistory.AppendText(Environment.NewLine)
RichTextBoxHistory.SelectionStart = RichTextBoxHistory.TextLength
RichTextBoxHistory.ScrollToCaret()
For Each client As ConnectedClient In mClients
If client.Connected Then
client.SendString(c.RemoteHost + ": " + c.RemotePort.ToString + " : " + s)
End If
Next
End If
End Sub
End Class
Public Class ConnectedClient
Private mClient As TcpClient = Nothing
Private mThread As Thread
Private mReceiveFunc As Form1.ReceiveDelegate
Private mStream As Sockets.NetworkStream = Nothing
Public ReadOnly Property Connected() As Boolean
Get
If mClient Is Nothing Then Return False
Return mClient.Connected
End Get
End Property
Public ReadOnly Property RemoteHost() As String
Get
If mClient Is Nothing Then Throw New Exception("Not Connected.")
Return CType(mClient.Client.RemoteEndPoint, IPEndPoint).Address.ToString()
End Get
End Property
Public ReadOnly Property RemotePort() As Integer
Get
If mClient Is Nothing Then Throw New Exception("Not Connected.")
Return CType(mClient.Client.RemoteEndPoint, IPEndPoint).Port
End Get
End Property
Public Sub New(ByRef Client As TcpClient, ByVal ReceiveFunc As Form1.ReceiveDelegate)
mClient = Client
mStream = mClient.GetStream()
mReceiveFunc = ReceiveFunc
mThread = New Thread(AddressOf ThreadFunc)
mThread.Start()
End Sub
Private Sub ThreadFunc()
mClient.NoDelay = True
Try
mReceiveFunc(Me, "connected.")
While mClient.Connected
Try
Dim i As Integer
i = mClient.Client.Available
If i > 0 Then
Dim b(i) As Byte
mClient.GetStream().Read(b, 0, i)
mReceiveFunc(Me, System.Text.Encoding.ASCII.GetString(b))
End If
Catch ex As Exception
If ex.InnerException IsNot Nothing Then
If ex.InnerException.GetType() Is GetType(SocketException) Then
Debug.Print("Socket Error. " + ex.Message)
End If
End If
End Try
Thread.Sleep(100)
End While
Debug.Print("Disconnected ThreadFunc")
Catch ex As ThreadAbortException
Catch ex As Exception
Debug.Print("ConnectedClient Error:" + Environment.NewLine + ex.ToString)
Finally
End Try
End Sub
Public Sub SendString(ByVal s As String)
If mClient Is Nothing Then Throw New Exception("Not Connected.")
Dim b() As Byte = System.Text.Encoding.ASCII.GetBytes(s)
If mClient IsNot Nothing Then
If mClient.Connected And mClient.GetStream().CanWrite() Then
Try
mStream.Write(b, 0, b.Length)
Catch ex As Exception
Debug.Print("Socket Write Error. " + ex.Message)
Close()
End Try
End If
End If
End Sub
Public Sub Close()
If mThread IsNot Nothing Then
mThread.Abort()
mThread.Join()
End If
If mClient IsNot Nothing Then
mClient.Close()
mClient = Nothing
End If
End Sub
Protected Overrides Sub Finalize()
Close()
End Sub
Public Overrides Function ToString() As String
If Connected Then
Return RemoteHost + ": " + RemotePort.ToString
Else
Return "Not connected."
End If
End Function
End Class
