How to detect whether barcode scanner is formatted with a "tab" suffix

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I have a VB.net program that has textboxes that get populated via a barcode scanner. For things to work properly, the barcode scanner needs to be formatted with a "Tab" suffix. Every once in a while, the barcode scanners get replaced and end up getting formatted with the wrong suffix. Usually what happens is they get formatted with an "Enter" vs a "Tab". This can sometimes cause issues because if a button has focus after the barcode, the enter will "click" the button. To address this issue, I am trying to write code to validate the barcode scanner is formatted with a "Tab". I thought I could use the keydown event but it is not detecting the tab from the barcode reader. I made sure I set the AcceptsTab property of the textbox to True and I also set the multiline property to true. If I actually press the tab key via the keyboard, it recognizes the tab but not from the barcode reader. I went ahead and reformatted the barcode reader to add the tab suffix and I can see the tab when I scan the barcode into NotePad. Any ideas on why this is not working? It is matters, I am using a Honeywell 3800G scanner with USB input.

What I have tried:

Private Sub TxtSequenceBarcode_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles TxtSequenceBarcode.KeyDown

        Debug.WriteLine("KeyDown = " & e.KeyCode)

        If e.KeyCode = Keys.Tab Then
            Debug.WriteLine("Tab Found via KeyDown")
        End If
    End Sub

Posted 31-Oct-18 4:52am

theskiguy

Updated 31-Oct-18 5:06am

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MadMyche 31-Oct-18 12:31pm

Do you have the ability to use the scanner management program to make sure it has the correct prefix/suffix

theskiguy 1-Nov-18 6:56am

Yes I do. As I mentioned above, I did reprogram it just to make sure. I first removed all suffixes and tested the output in Notepad and noticed there was no tab. I then added the tab suffix to the barcode reader and tested it again in Notepad and I could see the tab added.

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OriginalGriff · Answer 1 · 2018-10-31T05:07:00

The problem is that if the barcode scanner isn't set, it won't give you a TAB at all - it will just give you the numbers it scans, with no prefix or suffix info. And you can;t tell if that numeric infor was typed or scanned as Windows doesn't keep that kind of information.

The only way to detect the absence of a TAB is to set up a timer when you receive the actual data and clear if it you do receive a TAB key. If the timer expires after a "reasonable time (a couple of seconds maybe) then you didn't get a TAB.