hi JaiPrakash

      you will find good information regarding Design patterns on link
below

       http://www.dofactory.com/Patterns/Patterns.aspx

James

you may also want to check out Microsoft Patterns and Practices
http://msdn.microsoft.com/practices/

Are there particular patterns that you need help understanding?

There was a paper a couple of years ago that attempted to describe all the
uses of design patterns that the author discovered when reviewing the
framework.  Problem is: the framework is huge and patterns abound.  I think
he gave up.

Most common patterns, in my informal and unscientific guess, would be:
Factory, Abstract Factory, Strategy, Decorator, Adapter, Proxy, Template
Method, and Singleton.  (Caveat: That's literally off the top of my head.)

So, if you want to understand the patterns in the .Net framework, start by
reading about, and understanding, those.

(Hint: if you are completely lost, buy a copy of "Design Patterns Explained"
or "Head First Design Patterns").