How to use INumerable of SelectListItem for DropDownList in Asp.Net Mvc 6

With this example, it demonstrate all relational field between Primary Key and Foreign Key in order to retrieve the ID for DropDownList, I have an example below:

// From the controller of each class

public class TitlesController : Controller
{
    private readonly ApplicationDbContext _context;
    public IEnumerable<SelectListItem> Authors { get; set; }
    public IEnumerable<SelectListItem> Categories { get; set; }
    public IEnumerable<SelectListItem> Publishers { get; set; }

    public TitlesController(ApplicationDbContext context)
    {
        _context = context;    
    }

    // GET: Titles
    [Authorize(Roles = "admin")]
    public IActionResult Index()
    {
        var applicationDbContext = _context.Titles.Include(t => t.Authors).Include(t => t.Categories).Include(t => t.Publishers);
        return View(applicationDbContext.ToList());
    }

    // GET: Titles/Details/5
    [Authorize(Roles = "admin")]
    public IActionResult Details(int? id)
    {
        if (id == null)
        {
            return HttpNotFound();
        }

        Titles titles = _context.Titles.Single(m => m.TitleId == id);
        if (titles == null)
        {
            return HttpNotFound();
        }

        return View(titles);
    }
    private IEnumerable<SelectListItem> GetAllAuthors()
    {
        return _context.Authors.ToList().Select(authors => new SelectListItem
        {

            Text = authors.AuthorId.ToString(),
            Value = authors.AuthorId.ToString(),
        });
    }
    private IEnumerable<SelectListItem> GetAllCategories()
    {
        return _context.Categories.ToList().Select(categories => new SelectListItem
        {
            Text = categories.CatId.ToString(),
            Value = categories.CatId.ToString(),
            //Text = categories.CatName.ToString(),
            //Value = categories.CatName.ToString(),
        });
    }
    private IEnumerable<SelectListItem> GetAllPublishers()
    {
        return _context.Publishers.ToList().Select(publishers => new SelectListItem
        {
            Text = publishers.PubId.ToString(),
            Value = publishers.PubId.ToString(),
        });
    }

    // GET: Titles/Create
    [Authorize(Roles = "admin")]
    public IActionResult Create()
    {
        // Get all Authors Id in DropDownList
        Authors = GetAllAuthors();
        ViewBag.Authors = Authors;
        //ViewData["AuthorId"] = new SelectList(_context.Authors, "AuthorId", "Authors");

        // Get all Categories Id in DropDownList
        Categories = GetAllCategories();
        ViewBag.Categories = Categories;
        //ViewData["CatId"] = new SelectList(_context.Categories, "CatId", "Categories");

        // Get all Categories Id in DropDownList
        Publishers = GetAllPublishers();
        ViewBag.Publishers = Publishers;
        //ViewData["PubId"] = new SelectList(_context.Publishers, "PubId", "Publishers");
        return View();
    }

    // POST: Titles/Create
    [HttpPost]
    [ValidateAntiForgeryToken]
    [Authorize(Roles = "admin")]
    public IActionResult Create(Titles titles)
    {
        if (ModelState.IsValid)
        {
            _context.Titles.Add(titles);
            _context.SaveChanges();
            return RedirectToAction("Index");
        }
        // Get all Authors Id in DropDownList
        Authors = GetAllAuthors();
        ViewBag.Authors = Authors;
        //ViewData["AuthorId"] = new SelectList(_context.Authors, "AuthorId", "Authors");

        // Get all Categories Id in DropDownList
        Categories = GetAllCategories();
        ViewBag.Categories = Categories;
        //ViewData["CatId"] = new SelectList(_context.Categories, "CatId", "Categories");

        // Get all Categories Id in DropDownList
        Publishers = GetAllPublishers();
        ViewBag.Publishers = Publishers;
        //ViewData["PubId"] = new SelectList(_context.Publishers, "PubId", "Publishers");
        return View(titles);
    }

    // GET: Titles/Edit/5
    [Authorize(Roles = "admin")]
    public IActionResult Edit(int? id)
    {
        if (id == null)
        {
            return HttpNotFound();
        }

        Titles titles = _context.Titles.Single(m => m.TitleId == id);
        if (titles == null)
        {
            return HttpNotFound();
        }
        // Get all Authors Id in DropDownList
        Authors = GetAllAuthors();
        ViewBag.Authors = Authors;
        //ViewData["AuthorId"] = new SelectList(_context.Authors, "AuthorId", "Authors");

        // Get all Categories Id in DropDownList
        Categories = GetAllCategories();
        ViewBag.Categories = Categories;
        //ViewData["CatId"] = new SelectList(_context.Categories, "CatId", "Categories");

        // Get all Categories Id in DropDownList
        Publishers = GetAllPublishers();
        ViewBag.Publishers = Publishers;
        //ViewData["PubId"] = new SelectList(_context.Publishers, "PubId", "Publishers");
        return View(titles);
    }

    // POST: Titles/Edit/5
    [HttpPost]
    [ValidateAntiForgeryToken]
    [Authorize(Roles = "admin")]
    public IActionResult Edit(Titles titles)
    {
        if (ModelState.IsValid)
        {
            _context.Update(titles);
            _context.SaveChanges();
            return RedirectToAction("Index");
        }
        // Get all Authors Id in DropDownList
        Authors = GetAllAuthors();
        ViewBag.Authors = Authors;
        //ViewData["AuthorId"] = new SelectList(_context.Authors, "AuthorId", "Authors");

        // Get all Categories Id in DropDownList
        Categories = GetAllCategories();
        ViewBag.Categories = Categories;
        //ViewData["CatId"] = new SelectList(_context.Categories, "CatId", "Categories");

        // Get all Categories Id in DropDownList
        Publishers = GetAllPublishers();
        ViewBag.Publishers = Publishers;
        //ViewData["PubId"] = new SelectList(_context.Publishers, "PubId", "Publishers");
        return View(titles);
    }

    // GET: Titles/Delete/5
    [ActionName("Delete")]
    [Authorize(Roles = "admin")]
    public IActionResult Delete(int? id)
    {
        if (id == null)
        {
            return HttpNotFound();
        }

        Titles titles = _context.Titles.Single(m => m.TitleId == id);
        if (titles == null)
        {
            return HttpNotFound();
        }

        return View(titles);
    }

    // POST: Titles/Delete/5
    [HttpPost, ActionName("Delete")]
    [ValidateAntiForgeryToken]
    [Authorize(Roles = "admin")]
    public IActionResult DeleteConfirmed(int id)
    {
        Titles titles = _context.Titles.Single(m => m.TitleId == id);
        _context.Titles.Remove(titles);
        _context.SaveChanges();
        return RedirectToAction("Index");
    }
}

Then, from View Page of the Input DropDownList

<form asp-controller="Titles" asp-action="Create" method="POST"><div class="form-horizontal"><h4>Titles</h4><hr /><div asp-validation-summary="ValidationSummary.ModelOnly" class="text-danger"></div><div class="form-group"><label asp-for="AuthorId" class="col-md-2 control-label"></label><div class="col-md-10"><select asp-for="AuthorId" asp-items="@ViewBag.Authors" class="form-control"></select></div></div><div class="form-group"><label asp-for="BookCode" class="col-md-2 control-label"></label><div class="col-md-10"><input asp-for="BookCode" class="form-control" /><span asp-validation-for="BookCode" class="text-danger" /></div></div><div class="form-group"><label asp-for="BookTitle" class="col-md-2 control-label"></label><div class="col-md-10"><input asp-for="BookTitle" class="form-control" /><span asp-validation-for="BookTitle" class="text-danger" /></div></div><div class="form-group"><label asp-for="CatId" class="col-md-2 control-label"></label><div class="col-md-10"><select asp-for="CatId" asp-items="@ViewBag.Categories" class="form-control"></select></div></div><div class="form-group"><label asp-for="Notes" class="col-md-2 control-label"></label><div class="col-md-10"><input asp-for="Notes" class="form-control" /><span asp-validation-for="Notes" class="text-danger" /></div></div><div class="form-group"><label asp-for="Price" class="col-md-2 control-label"></label><div class="col-md-10"><input asp-for="Price" class="form-control" /><span asp-validation-for="Price" class="text-danger" /></div></div><div class="form-group"><label asp-for="PubDate" class="col-md-2 control-label"></label><div class="col-md-10"><input asp-for="PubDate" class="form-control" /><span asp-validation-for="PubDate" class="text-danger" /></div></div><div class="form-group"><label asp-for="PubId" class="col-md-2 control-label"></label><div class="col-md-10"><select asp-for="PubId" asp-items="@ViewBag.Publishers" class="form-control"></select></div></div><div class="form-group"><div class="col-md-offset-2 col-md-10"><input type="submit" value="Create" class="btn btn-default" /></div></div></div>

I want to use ViewData instead of ViewBag, but it does not work. Do you know how to modify this issue? Code as enjoying, thanks.