Question about event handler

[2005 user]

Hello,

I want to handle the events of my serial input buffer. I've seen the following article:

http://msdn.microsoft.com/en-us/libr...VS.100%29.aspx

My programming skills are not really that great so I've got a question:

How can I trigger a sub (for example: ArduinoSerialInput) as soon as this event is handled?

I've tried some code but without success, that's why I decided to post on the forum

Some pseudocode:
Code:

Public Delegate Sub SerialDataReceivedEventHandler(ByVal sender As Object, ByVal e As SerialDataReceivedEventArgs)

    Dim SerialBufferIn As SerialDataReceivedEventHandler = AddressOf ArduinoSerialInput


    Public Sub ArduinoSerialInput()

        MsgBox("test")

    End Sub

I use a piece of hardware to send data to my COM port, but nothing happens.

Is this a good approach? Some advice or suggestions please

[2005 user]

Private Sub comPort_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived

        MsgBox("test")

    End Sub

This works but is it the best way to go?

Cheers.

[NickThissen]

Private Sub comPort_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived

        MsgBox("test")

    End Sub

This works but is it the best way to go?

Cheers.

Yes. That (the Handles statement) is the most basic way of using an event.

[2005 user]

Thanks Nick (dank je!!)

[2005 user]

Hello,

Within this sub I want to append test to a Richtextbox at the end of the sub (Rtb1):

Private Sub comPort_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived

        Dim str As String = String.Empty
        Dim i As Integer
        Dim bytecount As Integer = SerialPort1.BytesToRead
        Dim byteBuffer(bytecount) As Byte

        Dim DisplayInput As String = String.Empty

        If bytecount > 0 Then

            SerialPort1.Read(byteBuffer, 0, bytecount)

        End If

        i = 0

        For i = 0 To bytecount 'Main for..Next loop to parse all data.

            If Convert.ToChar(byteBuffer(i)) = Chr(126) Then

                Do

                    DisplayInput = DisplayInput + Convert.ToChar(byteBuffer(i))

                    i = i + 1

                Loop Until Convert.ToChar(byteBuffer(i)) = Chr(35)

                'i = i + 1

                DisplayInput = DisplayInput + Chr(35)

                MsgBox(bytecount)
                MsgBox("i: " & i)
                MsgBox("Length: " & DisplayInput.Length.ToString)
                MsgBox("String: " & DisplayInput.ToString)

                Rtb1.AppendText(DisplayInput)

                DisplayInput = String.Empty

            End If

        Next

        i = 0

    End Sub

But I get the following error:

System.InvalidOperationException was unhandled

Message = "You are not allowed to perform an operation through various threads, there was another thread from a given access to the control Rtb1 than the thread on which the element was created."

Why can I not append text to the Richtextbox in this sub? I do not use it anywhere else??

Thanks

[NickThissen]

I am thinking that this problem has something to do with the serial port, which I know basically nothing about. So I'm going to leave this (hopefully) to someone with a little more knowledge on the subject if that's ok

[jmcilhinney]

The SerialPort raises its events on a secondary thread. As is always the case, if you want to access controls from a secondary thread you need to cross the thread boundary first. The most common way to do that is using the ISynchronizeInvoke interface, i.e. the InvokeRequired property and Invoke method. Follow the CodeBank link in my signature and check out my submission on Accessing Controls From Worker Threads, which explains how it's done.

[2005 user]

Ok,

Got it fixed,

Thanks!!