C#: a simple,modern,object-oriented,type-safe programming language.

 

VS is development tool. it includes an interactive development environment,visual designers for building windows and web applications,a compiler,and a debugger.

 

.NET Framwork:includes a common execution engine and a rich class library.

 

.NET Framework defines a "Common Language Specification"(CLS):a sort of lingua franca that ensures seamless interoperability between CLS-compliant languages and class libraries.---------->C# Language Specifiation

For C# developers,this means that even though C# is a new language.it has complete access to the same rich class libraries that are used by seasoned tools such as VB.net and VC.net.C# itselft does not include a class library.