@Html.DropDownList

    //后台     public ActionResult OrderAdd()
        {
            var items = new List<SelectListItem>()
            {
              (new SelectListItem(){Text = "男", Value = "Male"}),
              (new SelectListItem(){Text = "女", Value = "female"})
            };
            ViewBag.sexList = items;
            return View();
        }

//前端

//默认为空
@Html.DropDownList("sexList", ViewBag.sexList as  List<SelectListItem>,"")

//默认为第一个值，也就是 "男"
@Html.DropDownList("sexList", ViewBag.sexList as List<SelectListItem>)