TCP Listen to Stream and Print to textbox but nothing incomming

[lastyle]

Hi All,

i need to Listen on a TCP Port and the Result should be written to a textbox.

The Client opens a Connection to my Port, sends his data (asci chars , max 1024 bytes) and afterwards drops connection. Ive been trying with the following code but that way it doesnt work. I never used tcp stuff before and absolutely have no idea whats going wrong :-)

So generally i need to listen to a port (1581 in that case) and print it to a textbox or store it in a variable. I know that the data incimming starts with "ami" and ends with "eof"


Anybody who might help me out please ?

Imports System.Net.Sockets
Imports System.IO
Imports System.Net
Imports System.Text
Public Class Form1
    Dim stream As NetworkStream
    Dim streamw As StreamWriter
    Dim server As TcpListener
    Dim client As New TcpClient
    Dim ipendpoint As IPEndPoint = New IPEndPoint(IPAddress.Any, 1581)
    Dim t As New Threading.Thread(AddressOf Main)
    Dim datastring As String = Nothing
    Sub Main()
        Try
            server = New TcpListener(ipendpoint)
            server.Start()
            client = server.AcceptTcpClient
            client.ReceiveBufferSize = 1024
            Dim ns As NetworkStream = client.GetStream
            Dim data(client.ReceiveBufferSize) As Byte
            '---read incoming stream; Read() is a blocking call---
            Dim numBytesRead As Integer = ns.Read(data, 0, CInt(client.ReceiveBufferSize))

            While (numBytesRead <> 0)
                datastring = Encoding.ASCII.GetString(data, 0, numBytesRead)
                Console.Write(Encoding.ASCII.GetString(data, 0, numBytesRead))
                REM MsgBox(Encoding.ASCII.GetString(data, 0, numBytesRead))

            End While
        Catch
            MsgBox("error")
        End Try
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        If Button1.Text = "Start" Then
            t.Start()
            Button1.Text = "Stop"
        Else
            client.Close()
            streamw.Close()
            stream.Close()

            Button1.Text = "Start"
        End If
    End Sub
End Class

[jmcilhinney]

it doesnt work

This is never an acceptable description of a problem. You need to have debugged your code before posting here and you need to explain to us exactly what does happen and where and how that differs from your expectations. We may be able to find the issue by trawling through the code but we shouldn't have to work something out that you should already know.

[lastyle]

I am sorry for that.

the correct explantation is

The Textbox text doesnt change at all, it stays empty and
the messagebox only shows 16 chars, but there should be atleast 5xx up to 1000 , depending on amount of chars have been sent from the client.

[jmcilhinney]

That's still not a proper explanation. That's looking at it from a user's perspective. You're not a user. You're a developer, so use your development tools. If you don't know how to debug code then stop what you're doing and learn now, because it's an essential skill. Set a breakpoint at the top of your code and step through line by line, examining the course of execution and the state at each step. When either or both do not match your expectation, you have found an issue. That is what I mean by I say "where and how". You need to be able to tell us what the specific line of code was, what your expectation was and what the actual state/behaviour was.

[lastyle]

That's still not a proper explanation. That's looking at it from a user's perspective. You're not a user. You're a developer, so use your development tools. If you don't know how to debug code then stop what you're doing and learn now, because it's an essential skill. Set a breakpoint at the top of your code and step through line by line, examining the course of execution and the state at each step. When either or both do not match your expectation, you have found an issue. That is what I mean by I say "where and how". You need to be able to tell us what the specific line of code was, what your expectation was and what the actual state/behaviour was.

I know what you mean and already did so.

I know that the incomming data is bigger than 16 chars,but only the first 16 chars (bytes) have been read.

Why isnt this a proper description whan i say i am reading in a loop but still dont recieve more data ?

[lastyle]

I know what you mean and already did so.

I know that the incomming data is bigger than 16 chars,but only the first 16 chars (bytes) have been read.

Why isnt this a proper description whan i say i am reading in a loop but still dont recieve more data ?

Meanwhile i noticed that the incomming Stream isnt updated.

The client connects sends Data and then drops connection.The tcplistener doesnt accept the new connection and read new data from it. What is the best way to close and restart the TCPlistener ?

monitoring in a second thread which will abort thread one and restart it ?

my current code looks like this.

Imports System.Net.Sockets
Imports System.IO
Imports System.Net
Imports System.Text
Public Class Form1
    Dim stream As NetworkStream
    Dim streamw As StreamWriter
    Dim server As TcpListener
    Dim client As New TcpClient
    Dim ipendpoint As IPEndPoint = New IPEndPoint(IPAddress.Any, 1581)
    Dim t As New Threading.Thread(AddressOf Main)
    Dim datastring As String = Nothing
    Public bbsdata As String = Nothing
    Public bbsdataprevious As String = Nothing

    Sub Main()
        Try
            server = New TcpListener(ipendpoint)
            server.Start()
            client = server.AcceptTcpClient
            client.ReceiveBufferSize = 1024
            Dim ns As NetworkStream = client.GetStream
            Dim data(client.ReceiveBufferSize) As Byte
            datastring = ""
            '---read incoming stream; Read() is a blocking call---
            Dim numBytesRead As Integer = ns.Read(data, 0, CInt(client.ReceiveBufferSize))
            Dim z As Integer = 0
            While (numBytesRead <> 0)
                datastring = Encoding.ASCII.GetString(data, 0, numBytesRead)
                System.Diagnostics.Debug.WriteLine(Encoding.ASCII.GetString(data, 0, numBytesRead))
                SetTextBoxInfo(datastring)
            End While
        Catch
        End Try
    End Sub
    Public Sub SetTextBoxInfo(stringValue As String)
        If stringValue <> bbsdataprevious Then
            bbsdataprevious = stringValue
            Me.BeginInvoke(Sub() Me.TextBox2.Text = stringValue)
            datastring = ""
            client.Close()
            stream.Close()
        Else
        End If
    End Sub
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        If Button1.Text = "Start" Then
            t.Start()
            Button1.Text = "Stop"
        Else
            client.Close()
            stream.Close()

            Button1.Text = "Start"
        End If
    End Sub
End Class