scan multiple barcode in one textbox vb.net - vb.net

Question

For example i got two barcode, so i scan the two barcode at the textbox, it appear AVM12323AVM44454..
But I want it to be displayed in textbox for example like AVM12323, AVM44454. where there is a "," comma between the two code.
Previously i'm only tested for scan one barcode only in the textbox. So now i'm trying to scan more than one barcode in one textbox.
i have been looking the few example but not success.
Private Sub TextBoxMulti_TextChanged(sender As Object, e As EventArgs) Handles TextBoxMulti.TextChanged
Dim selectedMultiArrayScan As String()
Dim selectedMultiScan As String = ""
selectedMultiScan = TextBoxMulti.Text & ","
selectedMultiArrayScan = selectedMultiScan.Split(",")
End Sub
Private Sub MultiScan_Click(sender As Object, e As EventArgs) Handles MultiScan.Click
For Each stateName As String In selectedMultiArrayScan
//some query for each scanned item
Next stateName
End Sub

Answer 1

Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
Timer1.Enabled = False ' Fire only once
If TextBox1.Text.Trim <> "" Then TextBox1.Text += ", "
End Sub
Private Sub TextBox1_KeyUp(sender As Object, e As KeyEventArgs) Handles TextBox1.KeyUp
Timer1.Enabled = True
End Sub

Answer 2

Read the textbox with the event TextChanged like this:
If TextBox1.Text.Length >3 Then
Dim txt As String = Label1.Text + ", " + TextBox1.Text
If txt.Length = 6 Then txt = txt.Remove(0, 2)
Label1.Text = txt
'if you want to erase the text in TextBox1
TextBox1.SelectionStart = 0
TextBox1.SelectionLength = Label1.Text.Length
Try
End If
I use this code and it show the Barcodes in a label, you can replace the label to show in the textBox. Also, my Barcodes lenght always have 4 Alphanumeric characters. For you, Replace the If TextBox1.Text.Length >3 Then (3 to 8) to detect where a Barcode is readed.