Question

I’m new to .Net development, and now are following NerdDinner tutorial. Just wondering if any of you would be able to tell me

What is the differences between ViewData
and ViewModel

(all I know is they are used to pass some form of data from controller to view) and perhaps tell me on what situation should I use ViewData instead of ViewModel and vice versa

Thanks in advance!

Sally

Answer 1

ViewData:

In short, use ViewData as support data, such as a datasource to a SelectList.

ViewModel:

ASP.NET MVC ViewModel Pattern

When a Controller class decides to render an HTML response back to a
client, it is responsible for
explicitly passing to the view
template all of the data needed to
render the response. View templates
should never perform any data
retrieval or application logic – and
should instead limit themselves to
only have rendering code that is
driven off of the model/data passed to
it by the controller.

[…]

When using [the “ViewModel”] pattern we create strongly-typed
classes that are optimized for our
specific view scenarios, and which
expose properties for the dynamic
values/content needed by our view
templates. Our controller classes can
then populate and pass these
view-optimized classes to our view
template to use. This enables
type-safety, compile-time checking,
and editor intellisense within view
templates.