<form runat="server">
  <select id="ListBox" onserverchange="LeggiValore" Multiple="True" runat="server">
    <option value="1">Testo Elemento 1</option>
    <option value="2">Testo Elemento 2</option>
    <option value="3">Testo Elemento 3</option>
    <option value="4">Testo Elemento 4</option>
    <option value="5">Testo Elemento 5</option>
  </select>        <input type="submit" value="Test" />
</form>
<div id="Risultato" runat="server" enableviewstate="false" />
<SCRIPT language="VB" runat="server">

  Sub LeggiValore(objSender As Object, onjArgs As EventArgs)
    Dim objItem As ListItem
    Risultato.InnerHtml += "Sono stati selezionati i seguento oggetti:
"
    For Each objItem In objSender.Items
      If objItem.Selected Then
        Risultato.InnerHtml += objItem.Text & " <=> Valore: " & objItem.Value & "
"
    End If
    Next
  End sub

</SCRIPT>