These are not maintained projects. Feel free to reuse it if useful, feel free to PR, but don't expect fast answers in case of bug ;-).
I try to wrap each utility into a single file. Just drop the file you're interested in into your project.
Just a wrapper around Windows 'netstat' command (launch an external process).
For direct P/Invoke, see also: http://www.timvw.be/2007/09/09/build-your-own-netstatexe-with-c/
For managed (partial) implementation of netstat, see http://www.timvw.be/2007/09/09/build-your-own-netstatexe-with-c/