@golnazal:Hi Thanks !

As you have been so helpfull, can I also suggest that these two videos should be given the Functional Programming tag:

http://channel9.msdn.com/posts/MDCC-TechTalk-Classes-Jim-but-not-as-we-know-them

http://channel9.msdn.com/posts/MDCC-TechTalk-Fun-with-type-functions

Thanks again