Hi Kiro,
I'm assuming that you will be programming your device with the 
NI-DAQmx drivers (this is recommended).  National Instruments provides a native .NET API for NI-DAQmx. This is
available as a part of the NI-DAQmx driver.  There is a Knowledgebase article on our website 
here that provides more details on 
programming NI-DAQ in Microsoft Visual Basic .NET.  In addition, when you include .NET support in the installation of your DAQmx drivers, documentation is included and can be found in Start>Programs>National Instruments>NI-DAQ>NI-DAQmx .NET Framework 2.0 Help.
Regards,
Andrew W
National Instruments