How to convert a datetime to specific timezone in c#?

Question

I need help converting a DateTime to a specific time zone. What I have below is not working correctly.

gmTime = 03/02/2013 1:00:00 AM

 TimeZoneInfo timeZone = TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time");
 var time = timeZoneInfo.ConvertTime(gmTime, timeZone);

When I debug the value of time, which should be 03/01/2013 8:00:00 PM when the zone is applied, it comes back as 03/02/2013 1:00:00 AM.

If I do time.ToLocalTime() then I get the correct value. However, I need to convert time to different time zones.

Answer 1

DateTime objects have a "Kind" variable which helps TimeZoneInfo know how to treat it. In the MSDN documentation for TimeZone.ConvertTime it has the following:

DateTimeKind.Local, Converts the local time to the time in destinationTimeZone.

DateTimeKind.Utc, Converts Coordinated Universal Time (UTC) to the time in destinationTimeZone.

DateTimeKind.Unspecified, Assumed to be Local.

For example:

  Console.WriteLine("Local time zone is '{0}'.", TimeZoneInfo.Local.Id);

  var gmTime          = new DateTime(2013, 03, 02, 01, 00, 00, DateTimeKind.Utc);
  var localTime       = new DateTime(2013, 03, 02, 01, 00, 00, DateTimeKind.Local);
  var unspecifiedTime = new DateTime(2013, 03, 02, 01, 00, 00);

  var timeZone = TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time");

  var gmTimeConverted           = TimeZoneInfo.ConvertTime(gmTime,          timeZone); // 03/02/2013 8:00:00AM
  var localTimeConverted        = TimeZoneInfo.ConvertTime(localTime,       timeZone); // 03/02/2013 
  var unspecifiedTimeConverted  = TimeZoneInfo.ConvertTime(unspecifiedTime, timeZone);

  Console.WriteLine("Converting GMT         to EST: {0}", gmTimeConverted);
  Console.WriteLine("Converting Local       to EST: {0}", localTimeConverted);
  Console.WriteLine("Converting Unspecified to EST: {0}", unspecifiedTimeConverted);

Results in:

Local time zone is 'Pacific Standard Time'.
Converting GMT         to EST: 3/1/2013 8:00:00 PM
Converting Local       to EST: 3/2/2013 4:00:00 AM
Converting Unspecified to EST: 3/2/2013 4:00:00 AM

Or if your local timezone is 'Eastern Standard Time' you get these results

Local time zone is 'Eastern Standard Time'.
Converting GMT         to EST: 3/1/2013 8:00:00 PM
Converting Local       to EST: 3/2/2013 1:00:00 AM
Converting Unspecified to EST: 3/2/2013 1:00:00 AM

If you'd like TimeZoneInfo to treat 'Unspecified' like Utc, you should function like TimeZoneInfo.ConvertTimeFromUtc. Again from MSDN documentation

DateTimeKind.Local, Throws an ArgumentException.

DateTimeKind.Unspecified or DateTimeKind.Utc, Converts from Coordinated Universal Time (UTC).

Answer 2

Try something like the following Chace

TimeZoneInfo estTimeZone = TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time");
DateTime estDateTime = TimeZoneInfo.ConvertTimeFromUtc(timeUtc, estTimeZone);