private int GetNumbersControls()
        {
            ArrayList fields = null;
            try
            {
                fields = new ArrayList();
                //_page è un campo privato di classe istanziato e valorizzato
                //una sola volta come da Singleton pattern
                Type type = _page.GetType();
                if (type != null)
                {
                    foreach (FieldInfo field in type.GetFields(
                        BindingFlags.Public
                        | BindingFlags.Instance
                        | BindingFlags.Static
                        | BindingFlags.NonPublic
                        | BindingFlags.DeclaredOnly))
                    {
                        fields.Add(field.Name.ToString()
                            + " : " + field.Attributes.ToString()
                            + " [" + field.FieldType.FullName + "]");
                    }
                }
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }
            return fields.Count;
        }

      
        protected override void OnPreRender(EventArgs e)      
        {      
            ........................      
      
            base.OnPreRender(e);      
      
            ClientScriptManager cs = this.Page.ClientScript;      
      
            ........................      
      
            //Registrazione dello script personalizzato in pagina      
            ScriptManagerProxy sm = ScriptManagerProxy.GetInstance(this.Page, this);      
            cs.RegisterStartupScript(GetType(), SCRIPTCALLERKEY, sm.GetScript(this), true);      
        }