Key Value Database For Windows?

Berkeley DB is available. I'm surprised no-one has mentioned it yet.

You can build it on Windows either with a native or Cygwin toolchain, but it's probably best with MSVC if you're going to be linking it with C#.

c# asp.net windows memcached key-value

I would take a look at this article from highscalability.com. It describes a few options that you may want to consider, including Tokyo Cabinet/Tyrant, CouchDB and MongoDB.

c# asp.net windows memcached key-value

Redis is C99 (Posix). It should be trivial to build and run it on cygwin.

CodeHunter