TCP server/client

[lecfox]

Hello i have been following a tutorial and after finishing the server part wont run. can someone please help me with this error.

Error:

An unhandled exception of type 'System.StackOverflowException' occurred in System.Windows.Forms.dll

At this line:

Dim server As New clsServer

Code:

Imports System.Net
Imports System.Net.Sockets

Public Class clsServer

    Dim server As New clsServer

    Private Listener As TcpListener
    Private t As System.Threading.Thread
    Private reader As System.IO.StreamReader

    Public Clients As New Collection

    Public Sub StartListening()
       
        Listener = New TcpListener(IPAddress.Parse("127.0.0.1"), 6580)
        Listener.Start()
        t = New System.Threading.Thread(AddressOf ListenContinuously)
        t.Start()
    End Sub

    Public Sub StopListening()
        t.Abort()
    End Sub

    Private Sub ListenContinuously()
        While True = True

            If Listener.Pending = True Then
                AcceptClient()
            End If

            'PollForMessages() <This is for a later tutorial. That's why this line is commented out>
        End While
    End Sub

    Private Sub AcceptClient()
        Dim pendingClient As TcpClient
        Dim nameOfClient As String
        pendingClient = Listener.AcceptTcpClient()
        reader = New System.IO.StreamReader(pendingClient.GetStream)
        nameOfClient = reader.ReadLine()

        Clients.Add(pendingClient, nameOfClient)
        MessageBox.Show(nameOfClient & " has just signed in.")
    End Sub

    Private Sub btnStartServer_Click(sender As System.Object, e As System.EventArgs) Handles btnStartServer.Click

        server.StartListening()
        btnStartServer.Enabled = False
        btnStopServer.Enabled = True
    End Sub

    Private Sub btnStopServer_Click(sender As System.Object, e As System.EventArgs) Handles btnStopServer.Click

        server.StopListening()
        btnStopServer.Enabled = False
        btnStartServer.Enabled = True
    End Sub

    Private Sub clsServer_FormClosing(sender As Object, e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing

        server.StopListening()
    End Sub
End Class

I will need help with the client part as well.

[formlesstree4]

See, what you're doing is, inside the clsServer, you're re-initializing the server again:

Dim server As New clsServer

So every new instance of clsServer will continuously create new instances of the server.

[lecfox]

thank you for replying... but i really dont know how to fix that problem, even though you told me what is happening..
so how do i fix this?

[opus]

You should not create (or initialize) an instance of your class "clsserver" inside the code of that class, that would constitute an infinite loop (each new instance will create a new instance) resulting in a stack-overflow.
Instead you should initalize in the Main or MainForm-code. After that you can call the class-methods like "startListening and "StopListening".
However the Subs handling From-events should NOT be part of the clsserver-code!

[lecfox]

Not sure i understand fully or at all what you mean but i did try this based on what i think you meant.

Private Sub btnStartServer_Click(sender As System.Object, e As System.EventArgs) Handles btnStartServer.Click
        Dim server As New clsServer
        server.StartListening()
        btnStartServer.Enabled = False
        btnStopServer.Enabled = True
    End Sub

    Private Sub btnStopServer_Click(sender As System.Object, e As System.EventArgs) Handles btnStopServer.Click
        Dim server As New clsServer
        server.StopListening()
        btnStopServer.Enabled = False
        btnStartServer.Enabled = True
    End Sub

    Private Sub clsServer_FormClosing(sender As Object, e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
        Dim server As New clsServer
        server.StopListening()
    End Sub

i moved it from where it was and placed it in each sub where its needed and it works just fine with the client...

[opus]

I don't think that it wil work this way. You need to have the server declared only once just above all Subs in the MainForm-class.

[formlesstree4]

Public Class clsServer

    Dim server As New clsServer

    Private Listener As TcpListener
    Private t As System.Threading.Thread
    Private reader As System.IO.StreamReader

-snip-
End Class

The "Dim server As New clsServer" is causing your overflow.

[lecfox]

I know that is causing it but fixing it is the problem.. since the next tutorial is not up yet i have no idea what to do.

LINK to tut:
http://www.vbprogramming.8k.com/tutorials/LocalTCP.htm

[Evil_Giraffe]

The issue is that you've created a Form called clsServer. If you read through the tutorial carefully, you'll see that there are two code files involved. The first is a class called clsServer. This is not a Form! Later on, he creates a Form. This form uses a clsServer instance, and it is this form that includes the Dim server As New clsServer line. Since that is instantiating the class, not the form, this doesn't cause the infinite recursion.

You can either start again from scratch or try and figure out what goes in which file. If you're not too familiar with the concept of classes, instances and objects, I'd suggest starting from the beginning again.

[lecfox]

thank you Evil_Giraffe for pointing this out to me.. i guess i should have put the LINK in my first post.

[rohith900]

Hey upload ur full source code (zip)...ill help you solve ur problem...hopefully