MVC后台绑定dropdownList

  public ActionResult Index()
        {


            List<SelectListItem> items =  new List<SelectListItem>()
            {
                 new SelectListItem(){Text= " Income ", Value= " income "},
                 new SelectListItem(){Text= " Outcome ", Value= " outcome "},
            };


            SelectList generateList =  new SelectList(items,  " Value ",  " Text ");

            ViewBag.drList = generateList;
}     

@Html.DropDownList("listname",ViewBag.drList as SelectList,"请选择",new {@class="mylist",@id="listID"})