Converting Local Time To UTC

Question

I'm up against an issue storing datetimes as UTC and confused why this does not yield the same result when changing timezones:

var dt = DateTime.Parse("1/1/2013");
MessageBox.Show(TimeZoneInfo.ConvertTimeToUtc(dt, TimeZoneInfo.Local).ToString());

I am manually switching my local time zone on the machine between eastern and central.

Central yields 1/1/2013 6:00:00 AM, and Eastern yields 1/1/2013 5:00:00 AM. What am I missing here? They should be the same regardless of the time zone, correct?

Thanks so much in advance!

Answer 1

I think what you are missing is that the DateTime returned by your DateTime.Parse() statement doesn't come with a time zone. It's just a date and time that can be in any time zone. When you call TimeZoneInfo.ConvertTimeToUtc(dt, TimeZoneInfo.Local), you are telling it which time zone it starts in. So if you start in Central, you will get one answer, whereas if you start in Eastern, you will get an answer that is an hour earlier, UTC. Indeed, this is what your code shows.