Public Class Form1
    Public COM_Anschluss As String
    Public Bits_pro_Sekunde, Datenbits As Integer

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        COM_Anschluss = ComboBox1.Text
        Bits_pro_Sekunde = ComboBox2.Text
        Datenbits = ComboBox3.Text
        
        Form2.Show()
    End Sub


End Class

Public Class Form2
    Dim inputData As String = ""
    Dim zaehler As Integer = 0

    Public Event DataReceived As IO.Ports.SerialDataReceivedEventHandler

    Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        On Error GoTo ende

        '//Werte für einige Eigenschaften
        SerialPort1.PortName = Form1.COM_Anschluss
        SerialPort1.BaudRate = Form1.Bits_pro_Sekunde
        SerialPort1.Parity = IO.Ports.Parity.None
        SerialPort1.DataBits = Form1.Datenbits
        SerialPort1.StopBits = IO.Ports.StopBits.One
        SerialPort1.Handshake = IO.Ports.Handshake.None
        SerialPort1.RtsEnable = True

        '//Öffnen der seriellen Schnittstelle
        SerialPort1.Open()

ende:
    End Sub

    Private Sub SerialPort1_DataReceived(ByVal sender As System.Object, _
                      ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) _
                      Handles SerialPort1.DataReceived
        inputData = SerialPort1.ReadLine '//oder SerialPort1.ReadLine
        Me.Invoke(New EventHandler(AddressOf DoUpdate))

    End Sub

    Public Sub DoUpdate()

        TextBox1.Text = inputData
        TextBox2.Text = Len(inputData)
        zaehler = zaehler + 1
        TextBox3.Text = zaehler

    End Sub

    Private Sub Form2_FormClosed(ByVal sender As System.Object, _
                   ByVal e As System.Windows.Forms.FormClosedEventArgs) _
                   Handles MyBase.FormClosed
        '//Schließen der seriellen Schnittstelle
        SerialPort1.Close()
    End Sub

End Class