问题
How can I get universal time for a specified TimeZone, given a DateTime object? My application (a Timer) asks the user to specify a time and a timezone and I need to save the UTC based on the specified time+timezone values.
For example, user A specifies
DateTime: 07/06/2011 7:30 AM TimeZone: Eastern Standard Time (-5:00).
User B specifies:
DateTime: 07/06/2011 05:00 PM TimeZone: India Standard Time (+5:30).
I believe the UTC for both the above DateTime values will be the same and both of the above timers will occur at the same time. The problem is how do I get the UTC to save in the database? I am not able to get matching UTCs for the above datetime values.
回答1:
You can use DateTime in combination with TimeZoneInfo:
var utc = TimeZoneInfo.ConvertTimeToUtc(dateTimeAsEnteredByUser,
timeZoneChosenByUser);
You need to make sure, that the Kind property of dateTimeAsEnteredByUser is set to DateTimeKind.Unspecified.
BTW:
The two times you specified are not the same. The first is 12:30 UTC and the second one is 11:30 UTC. Additionally, 17:00 PM doesn't exist, it's either 17:00 or 5:00 PM.
回答2:
Converting to Utc:
DateTime utcDateTime = TimeZoneInfo.ConvertTimeToUtc(dateTime, timeZone);
来源：https://stackoverflow.com/questions/6595706/converting-datetime-timezone-to-utc