Сработало!
ViewModel
public IEnumerable<SelectListItem> Sites {get; set;}
public string SiteSelected {get; set;}
Контроллер
private IEnumerable<SelectListItem> GetAllSites()
{
return context.SITE.Select(x => new SelectListItem
{
Text = x.NAME,
Value = SqlFunctions.StringConvert((double)x.ID).Trim()
}).ToList();
}
siteViewModel.Sites = GetAllSites();
View
@Html.DropDownListFor(model => model.SiteSelected , Model.Sites)