rioting bits

A fast start with the solution (getting the current time in EST):

TimeZoneInfo timezone_EST = TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time");

DateTime now_EST = TimeZoneInfo.ConvertTimeFromUtc(DateTime.UtcNow, timezone_EST);

And now for the yada yada.

As standard as the ‘Eastern Standard Time’ might seem to you, C# doesn’t know a thing about it. In fact, it doesn’t know much about any timezone, except the local timezone (the one on the computer running the application) and the UTC.

Why that, it beats me. I would have expected to have at least the more used timezones kept inside the basic library. But I guess it wasn’t meant to be.

Instead, to get information about a specific timezone, you have to retrieve it from your system’s registry, with the FindSystemTimeZoneById method. This means you have to hardcode the timezone’s ID, and this after you made sure the computer that runs the code has your intended timezone with that ID in the registry.

To get a complete list of the timezones available on your system, you can go ahead and check the registry! (just joking, there’s a method for that)

Fortunately, these timezone IDs are pretty standard across Windows installations. And I’ll just throw here a list, to easily grab an ID when I need it (these are the timezones on my Windows 7; compared with a list I got from a Windows XP, there are ~7 different entries, rather obscure timezones):

If you like reading in-depth articles from the Creators, I highly recommend a post called A Brief History of DateTime, not by Stephen Hawking, on the BCL Team Blog. It’s about how the DateTime types evolved across .NET versions and how, in order to preserve backwards-compatibility and reliability, the usage of these types may not be that intuitive in some cases.