I know this is Hardware Analysis but I am sure there are some programmers here.
I am brand new to C# (I wrote a single Hello World program and that's it) but I have been using Java and only Java for years. Java has a well organized website where you can browse all of the built-in classes and learn the syntax of them:

http://java.sun.com/javase/6/docs/api/

I have looked everywhere and I couldn't find the equivalent of this for C#. I am completely lost without any API so please help!