VB TcpClient closes itself - vb.net

Question

right now I am stuck with something very easy but somehow my brain is stuck, is been a long time I have used VB and TCP functions and I have a slight idea of what is happening but I dont know how to solve it
I have a device that I need to connect using TCP, I open my connection in a function, then I want to send some data with another function that is in a separate class. Both functions are being called from somewhere else in the project, I think that what may be happening is that by opening the connection from another part of the project, when that function ends this also closes my connection and then the Tcp is not available when I want to send the data
These are axtracts of the code
Open and send data from here
Imports System.Net.Sockets
Imports System.Text
'Imports System.Threading
Public Class comms_management
Private avt_client As New TcpClient
Private netStream As NetworkStream
Private Avt_online As Boolean = False
Public Function TcpConnect(ip As String, port As Integer) As Boolean
Try
'configure TCP Client data
avt_client.SendTimeout = 1000
avt_client.ReceiveTimeout = 1000
avt_client.SendBufferSize = 4096
avt_client.NoDelay = True
'open TCP connection with AVT
avt_client.Connect(ip, port)
If avt_client.Connected Then
netStream = avt_client.GetStream()
Avt_online = True
MsgBox("Conexion exitosa", vbOKOnly)
Else
MsgBox("Error en conexion a AVT")
End If
Return True
Catch ex As Exception
MsgBox(ex.Message)
Return False
End Try
End Function
Public Function TcpDisconnect() As Boolean
avt_client.Close()
Return True
End Function
Public Function TcpSend(payload As String) As Boolean
Try
If avt_client.Connected Then
Dim payloadBytes As [Byte]() = Encoding.ASCII.GetBytes("message")
netStream.Write(payloadBytes, 0, payload.Length())
Dim incomingBytes(avt_client.ReceiveBufferSize) As Byte
netStream.Read(incomingBytes, 0, CInt(avt_client.ReceiveBufferSize))
Dim incomingMsg As String = Encoding.ASCII.GetString(incomingBytes)
MsgBox(incomingMsg)
Else
MsgBox("Unable to write")
End If
Return True
Catch ex As Exception
MsgBox(ex)
Return False
End Try
End Function
Public Function TcpReceive() As Boolean
End Function
End Class
This one manages the data to be sent
Public Class data_management
Const canEnable As String = "E1,99"
Const baudrate0 As String = "73,0A,00,04" '02 = 500000, 04 = 125000
Const maskmode0 As String = "73,2B,00,04" 'mask type 4
Const enableCan0 As String = "73,11,00,01" 'Enable can0
Const iso15765 As String = "73,26,00,01" 'Enable ISO 15765
Const qty_setup As Integer = 4
Dim AVT_comm As New AVT_853_Handling.comms_management
Public Function setup() As Boolean
Dim setup_step As Integer
Dim payload As String
For setup_step = 0 To qty_setup
Select Case setup_step
Case 0
payload = canEnable
Case 1
payload = baudrate0
Case 2
payload = maskmode0
Case 3
payload = enableCan0
Case 4
payload = iso15765
Case Else
End Select
AVT_comm.TcpSend(payload)
Next
Return 0
End Function
End Class
and this is from my form where I have the buttons to do stuff
Imports AVT_853_Handling
Public Class AVT_Form
Dim AVT_comm As New AVT_853_Handling.comms_management
Dim AVT_data As New AVT_853_Handling.data_management
Private Sub AVT_Form_Load(sender As Object, e As EventArgs) Handles MyBase.Load
End Sub
Private Sub ListBox1_SelectedIndexChanged(sender As Object, e As EventArgs)
End Sub
Private Sub btn_connect_Click(sender As Object, e As EventArgs) Handles btn_connect.Click
Dim ip As String
Dim port As Integer
Dim status As Boolean
Dim configSend As Integer
ip = txt_ip.Text
port = txt_port.Text
status = AVT_comm.TcpConnect(ip, port)
If (status = True) Then
lbl_avtStatus.Text = "AVT OK"
lbl_avtStatus.BackColor = Color.Green
Else
lbl_avtStatus.Text = "Error"
lbl_avtStatus.BackColor = Color.Red
End If
configSend = MsgBox("Enviar configuracion?", vbOKCancel + vbQuestion)
If (configSend = 1) Then
AVT_data.setup()
End If
End Sub
End Class
Tl;DR
I have a button to open a TCP connection in another class, then within the same button a third is class is called to send data to the TCP connection from the second class but the TCP connection is already closed but I have no idea how to solve it
Edit: I think the problem is that when I call my class "data_management" this creates a new object of "comms_management" and then this object has never opened a TCP client.
I am working on figuring this out