What event does a barcode reader fire off?

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.

VB Code:

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?

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

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.

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?

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().

VB Code:

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

Thank you. This is what I ended up with

VB Code:

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

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