OnChange DropDownList บน ASP.NET ต้องการอ่านค่าได้ด้วยวิธีไหนบ้างครับ

<script runat="server">

    Sub btnSubmit_OnClick(sender as Object, e As EventArgs)
        Me.lblText1.Text = Me.DropDownList1.SelectedItem.Text
    End Sub

    Sub DropDownList2_SelectedIndexChanged(sender as Object, e As System.EventArgs) Handles DropDownList2.SelectedIndexChanged
        Me.lblText2.Text = Me.DropDownList2.SelectedItem.Text
    End Sub

</script>