From: tst on
If this is related to your other question, then the answer would be no. LV can call .NET DLLs, but only on a platform which supports them and NXT does not.
As far as I know, the only official compiler for the NXT is the Mindstorms software and the LabVIEW toolkit, but I believe there are several other compilers for NXT made by users. I don't know if any of them would be C#, but it is likely that at least one will be C-based.