private AddCategoryViewModel MakeCategoryList()
 {
     var model = new AddCategoryViewModel();
     model.CategoriesList =
         _dataAccess.GetAllEntities()
             .Select(cat => new SelectListItem { Text = cat.CategoryName, Value = cat.CategoryId.ToString()});
     model.Category = new CategoryModel();
     model.Category.CategoryList = model.CategoriesList;
     model.Categories = _dataAccess.GetAllEntities();
     return model;
 }
 public ActionResult Index(AddCategoryViewModel model)
 {
     _dataAccess.AddNewEntity(model.Category);
     return RedirectToAction("Index", "ShowCategory");
 }