@Html.DropDownList("AuthorNamesFilter", AuthorNamesFilter, new { onchange = "$('form').submit();" })

[HttpPost]
        public ActionResult Edit(Guid id, string AuthorNamesFilter, string ApproverNamesFilter)
        {
                var proposal = _repo.FindProposalById(id);
                TryUpdateModel(proposal, null, null, _excludeList);

                ViewBag.DisplayList = GetFilteredDisplayList(proposal, AuthorNamesFilter, ApproverNamesFilter);

               return View(proposal);
}