public void Update(Foobar instance)
        {
            if (instance == null)
            {
                throw new ArgumentNullException("instance", "null");
            }

            instance.UpdateDate = DateTime.Now;

            this._Repository.Update(instance);
            this._Repository.SaveChanges();
        }
        public ActionResult Create(string name, string[] categories)
        {
            var foobar = new Foobar
            {
                Name = name,
                Categories = string.Join(",", categories)
            };

            if (ModelState.IsValid)
            {
                this.foobarService.Create(foobar);
                return RedirectToAction("Index");
            }

            var items = this.CategorySelectListItems();
            ViewBag.CategoryItems = items;

            return View(foobar);
        }