Init Problem? Serial Port Comm Program

[LostintheCode]

Hi all,

I am currently working on a project that requires me to split off a function from an already existing multi-use program that was created in house. We currently are working with serial port communication using a CAN-to-USB method.

I am a baby programmer and have been pulling hairs out trying to figure this program out, but to no avail. I am looking for any help, not necessarily hand-holding (I am willing to put in the work) but I would love to be able to get a good understanding of where my problems are and what I can do to prevent them in the future.

I have included a snippet of my button click event for checking/opening and writing to port. The references the init process, which is where I am getting my first error. I cannot seem to recognize the device when it is plugged in via USB.


Thank you for any and all help in advance. I know I have a lot to learn to get this running as smoothly as possible.

Also, please let me know if there is another part of the code needed to help out with this.

Thanks!
M

[Delaney]

Hello,

are you sure your device is on port com 2 ? you can find the list of port com available (as a collection of string) with My.Computer.Ports.SerialPortNames.
mdevice is apparently nothing so what is the code and where is it that assign something to mdevice.

for the second error, there is a "new" missing somewhere . which object is affected by this error ?

[LostintheCode]

Hi Delaney,

Once plugged into the CanBUS adapter, our programs communicate through COM2, yeah. I know it's a little unorthodox, but it has been that way since before I came onboard. I have attached a snippet of the sub that assigns mDevice. In regards to the second error, the error details point to the line " bal = mDevice.OpenBusAccessLayer()".

Thanks for the response!
M

[LostintheCode]

Hi Delaney,

Yeah, strangely enough, we use Port COM2 here. mDevice gets assigned under a private sub (photo attached), and the 2nd error is referencing the line "bal = mDevice.OpenBusAccessLayer()"

Thanks for the help!

Attachment 178464

[Delaney]

your attachment doesn't work and is not the good way to present the code (as it is poorly readable), please copy/paste the code between code tags ( click on # in the editor).

for the second error correct the declaration of bal in InitSocket :

dim bal as new Ixxat.......

[LostintheCode]

Ah, I see. That's fairly convenient to have this code paste feature.

The code where the mDevice is assigned:

Private Sub SelectDevice(ByVal DeviceEnumNumber As Long)
        'temporary holder for device tag
        Dim mTempDevice As Ixxat.Vci3.IVciDevice = Nothing
        Dim deviceHardwareID As Object
        Try
            'populate the device list, this section should be automated and removed
            deviceEnum = deviceList.GetEnumerator()
            deviceEnum.Reset()
            'continue as long as more devices are detected.   for our purpose number of devices will always be one
            Do While deviceEnum.MoveNext() = True
                mTempDevice = deviceEnum.Current
                If mTempDevice.VciObjectId = DeviceEnumNumber Then
                    mDevice = mTempDevice
                    ' a sample how to read the unique hardware ID from the device
                    deviceHardwareID = mTempDevice.UniqueHardwareId
                End If
            Loop
        Catch ex As Exception
            ' todo show the exception
        End Try
    End Sub

When I add new in the declaration of bal, I get an error that states I can't "use New on an interface"

[Delaney]

either deviceEnum or deviceList is empty or this mTempDevice.VciObjectId = DeviceEnumNumber is never achieved

let try to debug
put a msgbow("fail") in the catch part (to verify if you have an exception)

after that line :
mTempDevice = deviceEnum.Current
put a msgbox(mTempDevice.VciObjectId.tostring) to check what you get

[LostintheCode]

The errors remained the same. Attachment 178465 <-- This one is pointing to the bal = mDevice... line, and Attachment 178466 no message showed up for mTempDevice

[Delaney]

ok for the second error, it may not be a bal problem but a mdevice problem which is not created.

do you have somewhere in you code something like this (or close) :

dim mdevice as new Ixxat.Vci3.IVciDevice

by the way do you have on VS the option explicit on ON? if not put it...

[Delaney]

The errors remained the same. Attachment 178465 <-- This one is pointing to the bal = mDevice... line, and Attachment 178466 no message showed up for mTempDevice

that's means you don't go into the loop or the list is empty.
when do you call the sub select device ? before or after BtnTestStart ?

[LostintheCode]

ok for the second error, it may not be a bal problem but a mdevice problem which is not created.

do you have somewhere in you code something like this (or close) :

dim mdevice as new Ixxat.Vci3.IVciDevice

by the way do you have on VS the option explicit on ON? if not put it...

With the exception of the declaration statements

 Private mDevice As Ixxat.Vci3.IVciDevice = Nothing
    Private mCanChn As Ixxat.Vci3.Bal.Can.ICanChannel = Nothing
    Private mReader As Ixxat.Vci3.Bal.Can.ICanMessageReader = Nothing
    Private mWriter As Ixxat.Vci3.Bal.Can.ICanMessageWriter = Nothing
    Private mCanCtl As Ixxat.Vci3.Bal.Can.ICanControl = Nothing

I dont see mDevice being declared/defined anywhere else

[LostintheCode]

that's means you don't go into the loop or the list is empty.
when do you call the sub select device ? before or after BtnTestStart ?

Select device is being called before the btnTestStart. Would possibly moving it to the form load event help this?

[Delaney]

try to replace

Private mDevice As Ixxat.Vci3.IVciDevice = Nothing

by

Private mDevice As new Ixxat.Vci3.IVciDevice = Nothing

where do you declare that ?

Unfortunately, as it is late in France, I won't be able to help you more and much tonight (for me ).

[LostintheCode]

try to replace

Private mDevice As Ixxat.Vci3.IVciDevice = Nothing

by

Private mDevice As new Ixxat.Vci3.IVciDevice = Nothing

where do you declare that ?

Unfortunately, as it is late in France, I won't be able to help you more and much tonight (for me ).

I understand. Thank you for the help. The declaration of mDevice is in the form load event as shown

Public Class Form1
    'variables to run/initialize can connection
    Private mDevice As Ixxat.Vci3.IVciDevice = Nothing
    Private mCanChn As Ixxat.Vci3.Bal.Can.ICanChannel = Nothing
    Private mReader As Ixxat.Vci3.Bal.Can.ICanMessageReader = Nothing
    Private mWriter As Ixxat.Vci3.Bal.Can.ICanMessageWriter = Nothing
    Private mCanCtl As Ixxat.Vci3.Bal.Can.ICanControl = Nothing
    'device list variables, working to remove
    Private deviceManager As Ixxat.Vci3.IVciDeviceManager = Nothing
    Private deviceList As Ixxat.Vci3.IVciDeviceList = Nothing
    Private deviceEnum As IEnumerator = Nothing

When I change the code to

]Private mDevice As new Ixxat.Vci3.IVciDevice = Nothing

I get the error stating I cannot use "new" on an interface.

[Delaney]

I must confess that I am lost.

I manage to find an IXXAT sample vb.net program which is close to yours. and some manual. CAN bus is not something I know so I am afraid I won't be able to help you more than that. I don't have CAN device, so I cannot test it

I would advice you to start with that sample program and try to make it works and understand how it works and what are the difference with yours.

https://cdn.hms-networks.com/docs/li...sn=b3eb48d7_22

the link contains a large zip file with several sample programs in several language + manuals + api etc...

I found the link here : https://www.ixxat.com/technical-supp...olete-products

[LostintheCode]

I must confess that I am lost.

I manage to find an IXXAT sample vb.net program which is close to yours. and some manual. CAN bus is not something I know so I am afraid I won't be able to help you more than that. I don't have CAN device, so I cannot test it

I would advice you to start with that sample program and try to make it works and understand how it works and what are the difference with yours.

https://cdn.hms-networks.com/docs/li...sn=b3eb48d7_22

the link contains a large zip file with several sample programs in several language + manuals + api etc...

I found the link here : https://www.ixxat.com/technical-supp...olete-products

Thank you for the help, I will take a look at the sample files

[techgnome]

I understand. Thank you for the help. The declaration of mDevice is in the form load event as shown

Public Class Form1
    'variables to run/initialize can connection
    Private mDevice As Ixxat.Vci3.IVciDevice = Nothing
    Private mCanChn As Ixxat.Vci3.Bal.Can.ICanChannel = Nothing
    Private mReader As Ixxat.Vci3.Bal.Can.ICanMessageReader = Nothing
    Private mWriter As Ixxat.Vci3.Bal.Can.ICanMessageWriter = Nothing
    Private mCanCtl As Ixxat.Vci3.Bal.Can.ICanControl = Nothing
    'device list variables, working to remove
    Private deviceManager As Ixxat.Vci3.IVciDeviceManager = Nothing
    Private deviceList As Ixxat.Vci3.IVciDeviceList = Nothing
    Private deviceEnum As IEnumerator = Nothing

When I change the code to

]Private mDevice As new Ixxat.Vci3.IVciDevice = Nothing

I get the error stating I cannot use "new" on an interface.

Correct, you can't create an instancce of an interface... you can create an object that implements that interface, but an interface by itself cannot be instanciated.

ergo, if the mDevice isn't being created on the line it is declared on (also, I don't think you can New an instance and set it to nothing at the same time, because, what's the point? What's the intent? Do you want the object, or nothing? Can't have both.) ... it should be set somewhere else then (looks like inside SelectDevice).... which isn't happening, which may be due to the first error... What it sounds like is happening is that SelectDevice is failing to find the device, and as a result mDevice doesn't get set, and there's other code further downstream that's called that IS using mDevice with out first checking to see if it is not nothing... but since it is... error.

If it were me, I'd put a breakpoint on the first line of code in SelectDevice and then step through it, one line at a time, checking the value of everything, and seeing what it is really doing in there, and then working backwards to why it's not working as expected.
ie: it's not entering the loop because deviceEnum is empty... ok, so why is deviceEnum empty? Well, it's because deviceList is empty.... ok, why is deviceList empty then? Well, it's because ........ and so on...

-tg

[LostintheCode]

Correct, you can't create an instancce of an interface... you can create an object that implements that interface, but an interface by itself cannot be instanciated.

ergo, if the mDevice isn't being created on the line it is declared on (also, I don't think you can New an instance and set it to nothing at the same time, because, what's the point? What's the intent? Do you want the object, or nothing? Can't have both.) ... it should be set somewhere else then (looks like inside SelectDevice).... which isn't happening, which may be due to the first error... What it sounds like is happening is that SelectDevice is failing to find the device, and as a result mDevice doesn't get set, and there's other code further downstream that's called that IS using mDevice with out first checking to see if it is not nothing... but since it is... error.

If it were me, I'd put a breakpoint on the first line of code in SelectDevice and then step through it, one line at a time, checking the value of everything, and seeing what it is really doing in there, and then working backwards to why it's not working as expected.
ie: it's not entering the loop because deviceEnum is empty... ok, so why is deviceEnum empty? Well, it's because deviceList is empty.... ok, why is deviceList empty then? Well, it's because ........ and so on...

-tg

Tg,

That's a pretty solid idea. I know that deconstruction is a viable option, it's just so hard sometimes when you're stuck in your head on a problem. So I'm starting at the beginning of the updated button click event here

 Dim CurListViewItem As ListViewItem

        CurListViewItem = ListViewAvailInterfaces.SelectedItems(0)
        'disable get status timer
        TimerGetStatus.Enabled = False
        'if controller is already open, close existing before opening new one
        CloseCurrentExistingController()
        'get tag for currently selected item
        If CurListViewItem IsNot Nothing Then
            'MessageBox.Show(CurListViewItem.Tag.ToString())
            SelectDevice(CurListViewItem.Tag)
            InitSocket(0)
            'disable initialize button after it has been clicked
            ButtonInit.Enabled = False
            'enable getstatus timer again
            TimerGetStatus.Enabled = True
        End If

        'open a com port for use in sending serial commands to test card
        Try
            ' Get the selected COM port's name from the combo box.
            If Not myComPort.IsOpen Then
                myComPort.PortName = "COM2"
                ' Get the selected bit rate from the combo box.
                myComPort.BaudRate = 19200
                ' Set other port parameters.
                myComPort.Parity = Parity.None
                myComPort.DataBits = 8
                myComPort.StopBits = StopBits.One
                myComPort.Handshake = Handshake.None
                myComPort.ReadTimeout = 3000
                myComPort.WriteTimeout = 5000
                myComPort.ReadTimeout = 1000
                myComPort.WriteTimeout = 1000
                ' Open the port.
                myComPort.Open()
            End If
        Catch ex As InvalidOperationException
            MessageBox.Show(ex.Message)
        Catch ex As UnauthorizedAccessException
            MessageBox.Show(ex.Message)
        Catch ex As System.IO.IOException
            MessageBox.Show(ex.Message)
        End Try


        canMessage.Identifier = &H10A
        canMessage.DataLength = 8
        canMessage.Data(0) = "&H24"
        canMessage.Data(1) = "&H21"
        canMessage.Data(2) = "&H1E"
        canMessage.Data(3) = "&H1C"
        canMessage.Data(4) = "&H1A"
        canMessage.Data(5) = "&H18"
        canMessage.Data(6) = "&H16"
        canMessage.Data(7) = "&H14"

        If mWriter.Capacity > 0 Then
            mWriter.SendMessage(canMessage)
        End If

        System.Threading.Thread.Sleep(500)

        MessageBox.Show("OK")

        'While comTemp.Length < 1
        '    Try
        '        comTemp = myComPort.ReadLine()
        '    Catch ex As Exception

        '    End Try
        'End While

        'comTemp = ""




        canMessage.Identifier = &H10A
        canMessage.DataLength = 8
        canMessage.Data(0) = "&H00"
        canMessage.Data(1) = "&H11"
        canMessage.Data(2) = "&HF"
        canMessage.Data(3) = "&HD"
        canMessage.Data(4) = "&H7"
        canMessage.Data(5) = "&H5"
        canMessage.Data(6) = "&H26"
        canMessage.Data(7) = "&H25"

        If mWriter.Capacity > 0 Then
            mWriter.SendMessage(canMessage)
        End If

        System.Threading.Thread.Sleep(50)

        myComPort.Write("OK")



        canMessage.Identifier = &H10A
        canMessage.DataLength = 8
        canMessage.Data(0) = "&H00"
        canMessage.Data(1) = "&H2"
        canMessage.Data(2) = "&H23"
        canMessage.Data(3) = "&H22"
        canMessage.Data(4) = "&H20"
        canMessage.Data(5) = "&H1D"
        canMessage.Data(6) = "&H1B"
        canMessage.Data(7) = "&H19"

        If mWriter.Capacity > 0 Then
            mWriter.SendMessage(canMessage)
        End If

        System.Threading.Thread.Sleep(50)

        myComPort.Write("OK")



        canMessage.Identifier = &H10A
        canMessage.DataLength = 8
        canMessage.Data(0) = "&H00"
        canMessage.Data(1) = "&H15"
        canMessage.Data(2) = "&H13"
        canMessage.Data(3) = "&H12"
        canMessage.Data(4) = "&H10"
        canMessage.Data(5) = "&HE"
        canMessage.Data(6) = "&HC"
        canMessage.Data(7) = "&H8"

        If mWriter.Capacity > 0 Then
            mWriter.SendMessage(canMessage)
        End If

        System.Threading.Thread.Sleep(50)

        myComPort.Write("OK")



        canMessage.Identifier = &H10A
        canMessage.DataLength = 8
        canMessage.Data(0) = "&H00"
        canMessage.Data(1) = "&H4"
        canMessage.Data(2) = "&H27"
        canMessage.Data(3) = "&H1F"
        canMessage.Data(4) = "&H17"


        If mWriter.Capacity > 0 Then
            mWriter.SendMessage(canMessage)
        End If

        System.Threading.Thread.Sleep(50)

        myComPort.Write("OK")

      
    End Sub

and I'm looking at the lines

Dim CurListViewItem As ListViewItem

        CurListViewItem = ListViewAvailInterfaces.SelectedItems(0)

for

CurListViewItem = ListViewAvailInterfaces.SelectedItems(0)

The sub is

    Private Sub ListViewAvailInterfaces_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ListViewAvailInterfaces.SelectedIndexChanged
        ButtonInit.Enabled = True
        ShowDeviceHardwareID()
    End Sub

which leads me to

 Private Sub ShowDeviceHardwareID()
        Dim CurListViewItem As ListViewItem
        Dim selIndex As Windows.Forms.ListView.SelectedIndexCollection
        selIndex = ListViewAvailInterfaces.SelectedIndices()
        If selIndex.Count > 0 Then
            CurListViewItem = ListViewAvailInterfaces.SelectedItems(0)
            If CurListViewItem IsNot Nothing Then
                SelectDevice(CurListViewItem.Tag)
            End If
        End If
    End Sub

My question right off the bat is, looking at the code map that I sent above, isn't the Dim of CurLustViewItem in both places unneccessary, and also, I feel like there is an issue within the nested If statements. Like I posted originally, I am inheriting the code in this situation, and can't really speak on why it was constructed the way it was.

Thanks for any help with this.
M