☛ ViewData is a dictionary of objects that is derived from ViewDataDictionary class and accessible using strings as keys.

☛ ViewBag is a dynamic property that takes advantage of the new dynamic features in C# 4.0.

☛ ViewData requires typecasting for complex data type and check for null values to avoid error.

☛ ViewBag doesn't require typecasting for complex data type.

Calling of ViewBag is:

ViewBag.Name = "Hasan";

Calling of ViewData is :

ViewData["Name"] = " Hasan ";