To send error messages to views, which one is recommended? Using ViewBag or TempData?

Controller:

namesp开发者_JAVA技巧ace MvcMusicStore.Controllers
{
    public class StoreController : Controller
    {
        MusicStoreEntities db = new MusicStoreEntities();

        public ActionResult Index()
        {
            var genres = db.Genres.ToList();
            return View(genres);
        }

        public ActionResult Browse(string genre)
        {
            var g = db
                    .Genres
                    .Include("Albums")
                    .FirstOrDefault(x => x.Name == genre);

            if (g == null)
            {
                ViewBag.ErrorMessage = string.Format("Genre: {0} does not exist.", genre);
                TempData["ErrorMessage"] = string.Format("Genre: {0} does not exist.", genre);
                return View("Error");
            }

            return View(g);
        }

        public ActionResult Details(int id)
        {
            return View();
        }
    }
}

View:

@model System.Web.Mvc.HandleErrorInfo
@{
    ViewBag.Title = "Error";
}
<h2>
    ViewBag.ErrorMessage: @ViewBag.ErrorMessage
</h2>
<h2>
    TempData["ErrorMessage"]: @TempData["ErrorMessage"]
</h2>

Question:

To send data to views, which one is recommended? Using ViewBag or TempData?

Depends on what your page workflow is like. If you are using the Post-Redirect-Get pattern then you must use TempData because the ViewBag won't be available after the redirect.

Personally I only use one model per view and if I need to display errors I inject values into ModelState instead. That is what ModelState is for.