VB 2010 รับค่าจาก Serial Port ครับ สงสัยเกี่ยวกับการรับค่ามาครับ

 Private Sub SerialPort1_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
        ReceivedText(SerialPort1.ReadExisting()) 'Automatically called every time a data is received at the serialPort
    End Sub

    Private Sub ReceivedText(ByVal [text] As String)
        'compares the ID of the creating Thread to the ID of the calling Thread
        If Me.txtSN.InvokeRequired Then
            Dim x As New SetTextCallback(AddressOf ReceivedText)
            Me.Invoke(x, New Object() {(text)})
        Else
            Me.txtSN.Text &= [text]
        End If
    End Sub