public void cargaRoles()
        {
            RolDAO rolDao = new RolDAO();
            DropDawnRol.DataSource = rolDao.Consulta();
            DropDawnRol.DataTextField = "tipoRol";
            DropDawnRol.DataValueField = "id";
            // Bind the data to the control.
            DropDawnRol.DataBind();

            // Set the default selected item, if desired.
            DropDawnRol.SelectedIndex = 0;
        }