Using button to scroll down a Listbox control

Question

Hi,
I am creating a tool which will allow users to scroll down to each item one at a time from the Listbox. However I hit upon an out of range exception each time I try as the box exceeds its index limit. So far this is the code that sort of works for me but
I am sure that there is a better way:
Private Sub btnConfirm_Click(sender As Object, e As EventArgs) Handles btnConfirm.Click
Try
ListBox1.SelectedIndex += 1
Catch ex As ArgumentOutOfRangeException
MsgBox("End of UAT!", MsgBoxStyle.Information)
End Try
End Sub
I rather not generate an exception if I can contain this within a specified range but have been struggling to do so. So really what I am looking for would be something like this:
Get maximum number of items in the List box 
Dim numberOfItems As Integer = ListBox1.Items.Count
Create a range with numberOfItems being the upper limit 
Then let ListBox1.SelectedItem +=1 operate within this range and not go above.
I am not sure how I would implement this so any suggestions or pointers will be much appreciated.
Kind Regards,
MobileIAm 

Answer 1

You need to test what the SelectedIndex is before you add or subtract 1 from the SelectedIndex.
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
'move up through the items
If ListBox1.Items.Count > 0 Then
If ListBox1.SelectedIndex <= 0 Then
ListBox1.SelectedIndex = ListBox1.Items.Count - 1
Else
ListBox1.SelectedIndex -= 1
End If
End If
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
'move down through the items
If ListBox1.Items.Count > 0 Then
If ListBox1.SelectedIndex = ListBox1.Items.Count - 1 Then
ListBox1.SelectedIndex = 0
Else
ListBox1.SelectedIndex += 1
End If
End If
End Sub
If you say it can`t be done then i`ll try it