Serial port help

[nico123]

Dear all,
I have done a program using vb2005 to display reading from my microcontroller bs2 board but have encountered some problems. My code are as follows.

 Dim Stop_Rx As Boolean

    Private Sub btnRead_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnRead.Click

        SerialPort1.Open()

    End Sub

    Private Sub btnStop_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnStop.Click

        Stop_Rx = True

    End Sub

    Private Sub SerialPort1_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
        Dim Data As String = SerialPort1.ReadLine
        Dim reading1 As String
        Dim reading2 As String

        reading1 = CDbl(Data.Substring(0, 3))
        reading2 = CDbl(Data.Substring(3, 3))
        txt1.Text = reading1
        txt2.Text = reading2

        If Stop_Rx = True Then
            SerialPort1.Close()
        End If
    End Sub

End Class

I've encounter an error which is, (Cross-thread operation not valid: Control 'txt1' accessed from a thread other than the thread it was created on.)

 

[usminion]

It looks like your code is incomplete, can you show how txt1 is defined?

 

[usminion]

At second glance your code doesn't include any thread creation or execution. Without being able to see the full problem it will be near impossible for me to help. I found this by googling. Hopefully it helps.

 

[nico123]

txt1 is textbox1. I've name it txt1

 

[Robert_Zenz]

That one's easy.

The DataReceived-Event is fired from another Thread.

Add this to your code:

    Public Sub setTxt1Text(ByVal text As String)
        Me.txt1.Text = text
    End Sub

And then replace

        txt1.Text = reading1

with

        Me.txt1.Invoke(New Action(Of String)(AddressOf setTxt1Text), New Object() {"yourText"})

Of course, you'll ahve to the same thing with the second textbox.

For further information on this, have a Look at Invoke and MultiThreading.

Bobby

 

[nico123]

Because I am receiving data from my microcontroller. What should my "yourText" be in the Me.txt1.Invoke(New Action(Of String)(AddressOf setTxt1Text), New Object() {"yourText"}) ?? reading1 ???

 

[Robert_Zenz]

Exactly...forget to replace it, sorry.

 

[nico123]

Yes. Thank you very much I am able to get the readings but it changes very fast. Can I add a small delay to it ?