You don't need to handle the index of items (at least, not in this case).
You should use the same method you can see in the example project
(you should use the names of your views instead of Button and clv3, of course):
Sub Button_Click
Dim index As Int
index = clv3.GetItemFromView(Sender)
' Dim pnl As Panel
' pnl = clv3.GetPanel(index)
' Dim lbl As Label
' Dim chk As CheckBox
' lbl = pnl.GetView(0)
' chk = pnl.GetView(2)
' lbl.Text = "Clicked!"
' Msgbox("Item value: " & clv3.GetValue(index) & CRLF & "Check value: " & chk.Checked, "")
' This if you want remove the Item
clv3.RemoveAt(index)
End Sub