Why do we have ViewBag and ViewData if they are doing the same thing in ASP.NET Core MVC? Is there anything which ViewBag can do and ViewData can't - or vice versa?
Any specific scenario when should I prefer one over the other?
They are similar, but the main difference is that ViewBag use dynamic types, allowing a less complex syntax.
ViewBag.Example=DateTime.Now;
<p>Result: ViewBag.Example.Year </p>
Against that, the same with ViewData could be:
ViewData["Example"]=DateTime.Now;
<p>Result: @((ViewData["Example"] As DateTime).Year) </p>
So with ViewData you need casting, and you can receive errors when perform a "renaming", and you won't have the aid of Intellisense, for example.
Additionally, it seems to be "slower" (but not enough to be a problem). Example: ViewBag vs ViewData performance difference in MVC?