后台：  var d = new Criteria<CourseClass>()
.Desc(m => m.Id)
.Find();

IList<SelectListItem> list = new List<SelectListItem>();
foreach (CourseClass item in d)
{

list.Add(new SelectListItem { Text = item.Courseclass ,Value = item.Classid.ToString()});
}

                ViewData["list"] = list;

前台： <%:Html.DropDownListFor(model =>model.Courseclass,ViewData["list"] as IEnumerable<SelectListItem>)%>