.NET C# XBee 802.15.4 / Bluetooth

Two related questions:

Question 1:

I need to develop a PC/notebook app that can communicate over XBee 802.15.4. On my notebook I have an XBee USB Dongle that should communicate with e.g. an Arduino Uno that has a shield with an XBee on it.

Does .NET has libraries for communicating over 802.15.4 or is it "just" serial communication programming (since the XBee USB Dongle communicates over a COM port)?

Question 2:

On the other I also want to communicate over Bluetooth (PC to/from microprocessor board). Same question: are there .NET libraries to communicate over Bluetooth?

Many thanks.