I found device interface library in kdelibs-4.4.4\solid.
They are all .cpp & .h files.
Is it possible to use them with C# & Visual Studio 2008?
Please let me know.

Whilst I don't know about the Microsoft specific parts, Solid is usable on Windows to an extent I believe. Note that you will need a compiled libsolid.dll to be able to use your application.

I suggest asking the KDE Windows team for further information ( kde-windows@kde.org )