Convert UTC DateTime to another Time Zone

Question

I have a UTC DateTime value coming from a database record. I also have a user-specified time zone (an instance of TimeZoneInfo). How do I convert that UTC DateTime to the user's local time zone? Also, how do I determine if the user-specified time zone is currently observing DST? I'm using .NET 3.5.

Thanks, Mark

Answer 1

The best way to do this is simply to use TimeZoneInfo.ConvertTimeFromUtc.

// you said you had these already DateTime utc = new DateTime(2014, 6, 4, 12, 34, 0); TimeZoneInfo tzi = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time");  // it's a simple one-liner DateTime pacific = TimeZoneInfo.ConvertTimeFromUtc(utc, tzi); 

The only catch is that the incoming DateTime value may not have the DateTimeKind.Local kind. It must either be Utc, or Unspecified.

Answer 2

You can use a dedicated function within TimeZoneInfo if you want to convert a DateTimeOffset into another DateTimeOffset:

DateTimeOffset newTime = TimeZoneInfo.ConvertTime(     DateTimeOffset.UtcNow,      TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time") );