CS API is exported to other languages using Swig (
www.swig.org). Swig now supports C#, so it should be possible for CS to be accessible from C#. For this to happen, someone would need to add C# support to CS's Swig goop (CS/include/ivaria/cspace.i and other *.i files). The CS Swig goop is fairly modular, so adding C# support would involve coding up only the stuff which is specific to C#, rather than making an entire C# interface from scratch.