没有类型为'IEnumerable <selectlistitem>'的ViewData项具有“SupervisingPhysician”键

Question

在PatientViewModel

中

 public IEnumerable<SelectListItem> SupervisingPhysician { get; set; }

在PatientController中

// Supervising Physicians
List<SelectListItem> listSelectSPListItems = new List<SelectListItem>();
foreach (Physician physician in db.Physicians.Where(p => p.IsSupervising == true))
{
    SelectListItem selectSPList = new SelectListItem()
    {
        Text = physician.FirstName +" "+ physician.LastName,
        Value = physician.Id.ToString()
    };
    listSelectSPListItems.Add(selectSPList);
}
ViewBag.SupervisingPhysicians = new SelectList(listSelectSPListItems,"Value","Text");

在视图中

@Html.DropDownListFor(x => x.SupervisingPhysician, (SelectList)ViewBag.SupervisingPhysicians, htmlAttributes: new { @class = "form-control col-md-4" })

错误：

  

没有类型为'IEnumerable＆lt; SelectListItem＆gt;'的ViewData项有关键'监督医师'。