Hi Tom,
Welcome to the forum
I think I have a few guys from your company registered on here now.
I have been through a few VB.Net to C# conversions, it was a learning curve when I went through them seen as though I started out as a VB only guy. There are a few syntax gotcha's with doing a conversion using PISDK so be sure to post back when you hit them.
Michael is right (as always

) that you can pass the absolute date as a string. If you are working across time zones then be sure to make use of the PITime objects and TimeZone object from the connecting server. Also, if you are writing back to a collective then you need to manage passing the data around the collective members (e.g. PItoPI) until we get PISDK v1.4.
By the way, any reason why you are not using PI-BatchFL or PI-UFL for loading in the files to PI?
I like to think OSI followed my example of a PI developers forum, they do have a subscription based
OSISoft vCampus now.
Cheers,
Rhys.
OSIsoft PI System SpecialistsPI consultancy on PI Systems, PISDK, AFSDK, OLEDB etc and PI custom developments. Well pretty much anything to do with PI!