.net mvc DropDownListFor下拉列表使用（验证）方法

@Html.DropDownListFor(model => model.SchoolId, new SelectList(ViewBag.SelectList, "SchoolTypeId", "Name"), "请选择")//model.SchoolId类型Int            ViewBag.SelectList集合
@Html.ValidationMessageFor(model => model.SchoolTypeId, "", new { @style = "color:red" })//