What event does a barcode reader fire off?

[FastEddie]

I am trying to figure out how to do an automatic inventory look up using a barcode reader. Right now I have items in my database that I can retrieve by scanning an item and then tabbing out of the textbox with code like this.

Private Sub txtBarcode_Leave(ByVal sender As Object, _
        ByVal e As System.EventArgs) _
        Handles txtBarcode.LostFocus
 
        LookUpItem()
 
    End Sub

However, I want to be able to scan an item and have the lookup happen automatically without the user having to press tab, enter or mouse out of the text box. I have tried various textbox events but none have done what I need it to do.

After a scan an item I do get a sound like the scanner is trying to fire an event but the program doesn't know what to do with it. Any ideas?

[Merrion]

The TextChanged event should fire when the barcode reader fills the text box.

[jmcilhinney]

Most barcode scanners are connected to the keyboard port, although more and more are and will be USB. Basically, using a barcode scanner is akin to typing the same characters in from the keyboard. I could be wrong but I'm guessing that the TextChanged event will be raised for each character in the barcode, as opposed to just once for the whole thing.

[FastEddie]

jmcilhinney you are correct. The text changed does raise an event for each character in the code. The reader I am using is a USB device and as you stated it essentially a series of keyboard entries.

The more I have played with this device the more I am sure that that it is adding an "enter" at the end of the barcode. How would I go about trapping that enter and using it to do the look up?

[Fishcake]

instead of text_changed you could try using the keyPress event and then check if the KeyPress was a Carriage return and if it was then call LookUpItem().

if e.KeyChar = 13 then
    'If return key call LookUpItem()
End if

[FastEddie]

Thank you. This is what I ended up with

Private Sub txtBarcode_KeyDown(ByVal sender As Object, _
        ByVal e As System.Windows.Forms.KeyEventArgs) _
        Handles txtBarcode.KeyDown
 
        If e.KeyCode = Keys.Enter Then
            LookUpItem()
            ListBox1.Items.Add(lblItemName.Text)
            txtBarcode.Clear()
            txtBarcode.Focus()
        End If
    End Sub

[conipto]

Just a thought - Last time I made an app for a barcode scanner, I got stuck with one that couldn't be programmed to put enter after the read. I used a timer to find out how long it had been since the last character was entered, and if it was more than a second, I processed the barcode. Hopefully they'll stick with the one you've got

Bill