Problems about VB101SamplesBCL2 - UsingTheSerialPort. Pls help me :)

[Wanxi]

Hi everyone,

I am testing one of the example -> <UsingTheSerialPort> at VB101SamplesBCL2.

But there are some error which i don't know how to edit. I found some post that having the same problem with me.

I understand that i need to use Invoke method, because there is a different level of thread, so the update on the textBox is not valid..
But i really don't know where to add and what are the variables.

I at least need to show up something by this week. Pls help me.. :'(

This is the post from this forum that i found it from google.
Accessing Textboxes from threads
The answer over there is confusing me.. where is the head and tail?

The following is the program :
**The bold and underline is the error part..

ERROR: InvalidOperationException was unhandled
"Cross-thread operation not valid: Control 'textBox2' accessed from a thread other than the thread it was created on"

Also can refer to MyPreviousPost

Imports System
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Data
Imports System.Drawing
Imports System.Text
Imports System.Windows.Forms
Imports System.IO.Ports
 
Class Form1
    Inherits Form
 
    Public Sub New()
        InitializeComponent()
    End Sub 'New
 
    Private stopBits, parity As Array ' arrays to access the enumerations in System.IO.Ports
    Private validStopBits As New ArrayList() ' ArrayLists hold the valid values for this machine
    Private validParity As New ArrayList()
 
 
    ' Send the text in the text box to the serial port.
    ' The data should stay in the buffer until received by the event handler.
    Private Sub SendButton_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click
        Try
            ' Write a line to the serial port
            SerialPort1.WriteLine(textBox1.Text)
        Catch ex As System.Exception
            MessageBox.Show(ex.Message)
        End Try
    End Sub 'SendButton_Click
 
 
    ' Event handler for data reception
    Private Sub serialPort_DataReceived(ByVal sender As Object, ByVal e As SerialDataReceivedEventArgs)
        ' Read the buffer to the text box.
        textBox2.Text = SerialPort1.ReadLine()
    End Sub 'serialPort_DataReceived
 
 
    ' Load the form and set up parameters from the default serial port.
    ' Open the port and prepare it for IO.
    Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
        Try
            ' Open the serial port
            SerialPort1.Open()
            ' Set the event handler for data reception
            AddHandler SerialPort1.DataReceived, AddressOf serialPort_DataReceived
        Catch ex As System.Exception
            MessageBox.Show(ex.Message)
        End Try
        label11.Text = SerialPort1.PortName
 
        label2.Text = SerialPort1.BaudRate.ToString()
        label4.Text = SerialPort1.StopBits.ToString()
        label6.Text = SerialPort1.Parity.ToString()
        label8.Text = SerialPort1.DataBits.ToString()
        label10.Text = SerialPort1.RtsEnable.ToString()
 
        ' Populate the stop bits box with all valid options.
        ' Note that the serial port must be open to accurately test the options.
        comboBox1.SelectedText = SerialPort1.StopBits.ToString()
        Dim currentStopBitSetting As System.IO.Ports.StopBits = SerialPort1.StopBits
 
        stopBits = [Enum].GetValues(GetType(System.IO.Ports.StopBits))
        Dim sbtype As System.IO.Ports.StopBits
        For Each sbtype In stopBits
            ' test to make sure the machine supports the setting
            Try
                SerialPort1.StopBits = sbtype
                validStopBits.Add(sbtype)
                comboBox1.Items.Add(sbtype)
            Catch ' ignore this entry as invalid
            End Try
        Next sbtype
        SerialPort1.StopBits = currentStopBitSetting
 
        ' Populate the parity with valid options
        comboBox2.SelectedText = SerialPort1.Parity.ToString()
        Dim currentParitySetting As System.IO.Ports.Parity = SerialPort1.Parity
        parity = [Enum].GetValues(GetType(System.IO.Ports.Parity))
        Dim ptype As System.IO.Ports.Parity
        For Each ptype In parity
            ' test to make sure the machine supports the setting
            Try
                SerialPort1.Parity = ptype
                validParity.Add(ptype)
                comboBox2.Items.Add(ptype)
            Catch ' ignore this entry
            End Try
        Next ptype
    End Sub 'Form1_Load
 
 
    ' Respond to the form closing event by closing the SerialPort instance. 
    Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As FormClosingEventArgs)
        SerialPort1.Close()
    End Sub 'Form1_FormClosing
 
 
    ' The following methods demonstrate the ability to set parameters of the serial port
    ' through the SerialPort instance.  The baud rate of the port will be set in response to
    ' the corresponding button clicks.
    Private Sub button3_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button3.Click
        SerialPort1.BaudRate = 1200
        label2.Text = SerialPort1.BaudRate.ToString()
    End Sub 'button3_Click
 
 
    Private Sub button4_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button4.Click
        SerialPort1.BaudRate = 4800
        label2.Text = SerialPort1.BaudRate.ToString()
    End Sub 'button4_Click
 
 
    Private Sub button5_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button5.Click
        SerialPort1.BaudRate = 9600
        label2.Text = SerialPort1.BaudRate.ToString()
    End Sub 'button5_Click
 
 
    Private Sub comboBox1_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs) Handles comboBox1.SelectedIndexChanged
        SerialPort1.StopBits = CType(validStopBits(comboBox1.SelectedIndex), System.IO.Ports.StopBits)
        label4.Text = SerialPort1.StopBits.ToString()
    End Sub 'comboBox1_SelectedIndexChanged
 
 
    Private Sub comboBox2_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs) Handles comboBox2.SelectedIndexChanged
        SerialPort1.Parity = CType(validParity(comboBox2.SelectedIndex), System.IO.Ports.Parity)
        label6.Text = SerialPort1.Parity.ToString()
    End Sub 'comboBox2_SelectedIndexChanged
 
End Class 'Form1

Please reply me as soon as possible.
Thank you very much :)

Regard
Wanxi