Hi Venkit,
There are examples in CVI located in Help >> Example Finder. For the DLL examples, navigate to Communicating with External Applications >> Using External Code >> Integrating DLLs. The most basic examples are usecvidll.prj, useguidll.prj, useit.prj, usescope.prj, and scope.prj.
Also, here are some KnowledgeBase articles that may help:
Cheers,
David Goldberg
National Instruments
Software R&D