protected void Button2_Click(object sender, EventArgs e)
        {
            if (HiddenField1.Value == "true")
            {
                Panel1.Controls.Clear();
            }
            else
            {
                HiddenField1.Value = "true";
            }

            XMLTransformer transf = new XMLTransformer();

            foreach (WebControl w in transf.ListOfControls(DropDownList1.SelectedValue))
            {
                Panel1.Controls.Add(w);
                Panel1.Controls.Add(new LiteralControl("<br />"));
            }
        }
        protected void Page_Load(object sender, EventArgs e)
        {
            string validade = HiddenField1.Value;

            if (!IsPostBack)
            {
                XMLReader RedEngine = new XMLReader();
                DropDownList1.DataSource = RedEngine.ListOfListBox();
                DropDownList1.DataBind();
            }
            else if (validade == "true")
            {
                Panel1.Controls.Clear();

                XMLTransformer transf = new XMLTransformer();
                foreach (WebControl w in transf.ListOfControls(DropDownList1.SelectedValue))
                {
                    Panel1.Controls.Add(w);
                    Panel1.Controls.Add(new LiteralControl("<br />"));
                }
            }
        }