combobox and 3 listboxs

Hi
Having some trouble with this.

Please can someone help

I have a combobox and 3 listboxs and if a product that is selected from the combobox is already in the list box, then update the quantity (say there is already 4 tins of beans in there and you want to have 6 tins of beans) I have to up bate the original quantity to 6 with out making a new row, and the price listbox is the same

I have some code but don’t know if its right

If lstProduct.Items.Contains(cboProduct.SelectedItem) = True Then
Dim msg As String
Dim title As String
Dim style As MsgBoxStyle
Dim response As MsgBoxResult
msg = "You have already placed that item in your shopping trolley. Do you wish to change the quantity in your trolley to the new Quantity?"
style = MsgBoxStyle.YesNo
title = "MsgBox "
response = MsgBox(msg, style, title)
If response = MsgBoxResult.Yes Then

For Index = 0 To lstProduct.Items.Count - 1
Do Until



Loop

Next
End If
End If

One thing I can help you with is the way you write a message box.

Try writing it like this:

Msgbox("You have already placed that item in your shopping trolley. Do you wish to change the quantity in your trolley to the new Quantity",MsgBoxStyle.YesNo,"MsgBox")

It takes up a little less room!