不熟悉asp.net-mvc下拉列表

Question

我在一个PartialView中有一个下拉列表但不起作用

我的控制器

public ActionResult Create()
        {

            var University = from s in db.CAMPUS_UNIVERSITY
                              join u in db.UNIVERSITY on s.IdUniversity equals u.IdUniversity
                              select u;


             ViewBag.IdUniversity = new SelectList(University, "IdUniversity", "Name");


            return View();
        }

我的部分观点

@model RolesMVC3.Areas.Superusuario.Models.CampusViewModel

@using (Html.BeginForm())
{
@Html.DropDownListFor(model => model.IdUniversidty,
new SelectList(ViewBag.IdUniversity as System.Collections.IEnumerable, "IdUniversity", "Name"),
"-- select university --", new { id = "university" })


}

和ViewModel

public class CampusViewModel
    {
        public int IdUniversity { get; set; }
        [Required]
        public string Name { get; set; }
        public virtual ICollection<CITY> City { get; set; }
    }
}

我收到了这些错误

DataBinding：'System.Web.Mvc.SelectListItem'不包含 名为'IdUniversity'的财产。