Is there a functional difference between ViewState in Webforms and ViewBag in MVC? They seem to be the "same thing". And can be used in the same ways. I ask because MVC promotes the stateless Web and not stuffing data in the page causing bloat and slower performance. But it seems that you can do that in MVC as well. All they did, seemingly, is just give it a new name.
ViewState in Web Forms was serializing form data into a hidden, encrypted field in the form, so data could be re-bound on the postback.
ViewBag/ViewData is a dictionary where you can "stuff" data into. For example, you might add to it in your Controller, then access it in your View. The data is dynamic which makes it difficult to work with the data. ViewBag doesn't get sent to the client, it's part of the MVC (server pipeline).
Both should be avoided.
ViewState by, well, not using it and finding workarounds. And ViewBag should be avoided by the use of ViewModels.