Talking about VS, I haven't done a lot of research but has anyone had some luck using emacs on windows for C#?
I don't program C#, but there is OmniSharp for Emacs: https://github.com/OmniSharp/omnisharp-emacs & you can look to csharp-mode page on emacswiki: http://www.emacswiki.org/emacs/CSharpMode (and this post: https://bbbscarter.wordpress.com/2013/08/17/c-autocompletion...)
P.S. There were C# parser for CEDET (in contrib), but it wasn't updated for a long time
A lot of commercial IDEs are very well integrated with language and toolset, but often they're really not very good text editors (Visual Studio, I'm looking at you)