Probleme SerialPort

Code :
OptionExplicitOn
Imports System
Imports System.IO
Imports System.IO.Ports
Imports System.Text
Imports Microsoft.VisualBasic
 
PublicClass Form1
 
    Private MonPort AsNew PortSerie
    Dim returnStr AsString = ""
 
    PrivateSub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs)HandlesMyBase.Load
        LoginForm1.ShowDialog()
        Me.Text = "Terminal VIZ 100"
        Me.WindowState = FormWindowState.Maximized
        Send_Num.Enabled = False
        Num_serie_recup.Text = ""
    EndSub
 
    PrivateSub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)Handles Button1.Click
        Form2.ShowDialog()
    EndSub
 
    PrivateSub Send_Num_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)Handles Send_Num.Click
        ProgressBar1.Value = 0
        SendSerialData(Form2.N_Serie)
    EndSub
 
    PrivateSub Receive_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)Handles Receive.Click
         ProgressBar1.Value = 0         
         ReceiveSerialData()
    EndSub
 
    PrivateSub ProgressBar1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)Handles ProgressBar1.Click
        ProgressBar1.Minimum = 0
        ProgressBar1.Maximum = 200
    EndSub
 
    Sub SendSerialData(ByVal data AsString)
        MonPort.configuration()
        Using PortSerie As IO.Ports.SerialPort = My.Computer.Ports.OpenSerialPort("COM1")
            MonPort.ouverture()
            PortSerie.WriteLine(data)
            ProgressBar1.Value += 100
            PortSerie.Close()
            ProgressBar1.Value += 100
            MonPort.fermeture()
        EndUsing
    EndSub
 
    Function ReceiveSerialData()AsString
        MonPort.configuration()
        Using PortSerie As IO.Ports.SerialPort = My.Computer.Ports.OpenSerialPort("COM1")
            MonPort.ouverture()
            If(SerialPort.IsOpen())Then
                Do MsgBox("Ouverture réussi", MsgBoxStyle.Information)
                    ProgressBar1.Value = 70
                    Dim Incoming AsString = PortSerie.ReadLine()
                    If Incoming IsNothingThen
                        ExitDo
                    Else
                        returnStr &= Incoming & vbCrLf
                    EndIf
                    ProgressBar1.Value = 120
                Loop
            EndIf
            ProgressBar1.Value = 150
            MonPort.fermeture()
        EndUsing
        Return returnStr
        ProgressBar1.Value = 200
    EndFunction
 
EndClass
 
 
#Region"Classe Port Série"
PublicClass PortSerie
 
    Public NoPort AsString = "COM1"'Numero de port qui sera utilisé
    Public Debit AsInteger = 9600'debit en bits/sec sur le port COM
    Public NbBits AsInteger = 8'bits de donnée
    Public BitStop AsString = IO.Ports.StopBits.One'bit de stop 
    Public Parite AsString = IO.Ports.Parity.None'parité
 
    Dim i AsInteger
 
    Function configuration()AsBoolean
        Form1.SerialPort.PortName = NoPort
        Form1.SerialPort.BaudRate = Debit
        Form1.SerialPort.DataBits = NbBits
        Form1.SerialPort.StopBits = BitStop
        Form1.SerialPort.Parity = Parite
    EndFunction
 
    Function ouverture()AsBoolean
        ' verifie que le port est fermé avant de l'ouvrir
        If(Not(Form1.SerialPort.IsOpen)Or(NoPort = "NULL"))Then
            Form1.SerialPort.Open()
        EndIf
        ouverture = EtatPort()
    EndFunction
 
    Function fermeture()AsBoolean
        ' verifie que le port est ouvert avant de le fermer
        If(Form1.SerialPort.IsOpen())Then
            Form1.SerialPort.Close()
        EndIf
        fermeture = EtatPort()
    EndFunction
 
    Function EtatPort()AsBoolean
        ' test le port et retourn 0 ou 1
        If(Form1.SerialPort.IsOpen())Then
            EtatPort = True
        Else
            EtatPort = False
        EndIf
    EndFunction
 
   
EndClass
#End Region