I am brushing up on my design patterns at the moment and got a little confused when I came across this tutorial:

<http://www.asp.net/mvc/tutorials/iteration-4-make-the-application-loosely-coupled-cs> 

If you look at listing 7 onwards, the author says it is using the decorator pattern. However, is one of the main principles of this pattern to wrap objects and ADD responsibilities and behaviour?

I think it looks more like and adapter pattern as it is adapting the MVC specific ModelStateDictionary to work with a more flexible IValidationDictionary so that different implementations can be used with the service if WPF etc were used instead. There is new responsibility or behaviour added.

Do I have this correct or not? If I'm wrong can anyone please explain why?

Thanks