Short answer: Yes.
Long answer: Depends. (Obligatory XKCD).
Our SNAP Brains are ModbusTCP slaves out of the box, so groov can read and write anything that has a MMP address on them with no other software required.
Check out @mstjohn nice table of Modbus device settings table here for exactly how to set up groov to talk to our SNAP Brains ; http://forums.opto22.com/t/groov-your-modbus-device-settings-tips/821
Also, note how wonderfully her table shows the problem with having a Modbus standard.... There are so many ways to interpret the data... bleh.... Anyway, point is, as long as your .NET library is sort of close to one or more of these 'standards', groov will (should) be flexible enough to read and write the data.
While I don't know of anyone using .NET to emulate a ModbusTCP slave for groov to talk to it, I would not be surprised if someone hasn't done it.