It seem like mvc 3 team decided to bring in a feature for dynamic data exchange between a controller and a view called the viewbag but it is A good thing against the strongly typed view we all know about? What are some of the positive and negative aspects to using the ViewBag versus using a strongly typed view?
The ViewBag is the same thing as ViewData in previous ASP.NET MVC 1 and 2. It just happens to be dynamic instead of needing to use it like a dictionary with keys. I don't think this will replace strongly typed views at all and in fact you should use Viewdata/Viewbag as little as possible. Always use strongly typed views whenever possible since it will lead to fewer errors if the names in your Viewdata/Viewbag change and make the HTML cleaner by not having ViewData casts all over the place.
来源：https://stackoverflow.com/questions/4766062/is-using-viewbag-in-mvc-bad