If you want to follow the .NET samples available by adesk, download the VS express (it is free too), once you became somehow familiar and want to use sharpD.... then is up to you.
Look for the document: Ecma-334.pdf where you can read about the language specification, it is available in the microsoft web or here:
http://www.andymcm.com/csharpfaq.htm#2.6As you can see or being find out, it is a lot of reading and researching ahead.
In my own personal opinion it is much easier coming from lisp to move into objectarx, and from there it can be less painful the transition to C#...
Also, you need to mention what acad version you are using, I read from some masters that does not worth the effort to produce C# code for pre-2006 acad versions.... but that is just a comment.