Dynamic Dropdown webpart property

I have to create a dropdown webpart property but the values of that property has to come from data from the site. How can I create dinamically that enum to populate the dropdown like the listeRendu enum is populating the ListeRendu property? Thanks

        public enum listeRendu        {            Crossfade = 0,            Scroll        };        //create get/set for the property        protected listeRendu _listeRendu;        [Category("WebPart Configuration")]        [WebPartStorage(Storage.Shared)]        [WebDisplayName("Type de rendu")]        [WebDescription("Type de rendu")]        [WebBrowsable(true)]        [Personalizable(true)]        public listeRendu ListeRendu        {            get { return _listeRendu; }            set { _listeRendu = value; }        }