Get offset minutes from timezone (string) with NodaTime

Question

What's the easiest way to get the minutes if I only have a string that represents the timezone? (for example "Europe/London")

So far I have:

public static int ConvertFromTimeZoneToMinutesOffset(string timeZone)
{
    DateTimeZone zone = DateTimeZoneProviders.Tzdb[timeZone];

    // Need magic code to get offset as minutes
}

But I'm not finding an easy approach to convert it to minutes.

NOTE: What I need is the offset in that specific moment in which the code is being executed. Between that timezone and UTC.

What offset? It varies over time. Right now it's 60 minutes, but on October 30th it will go back to 0... — Jon Skeet, Oct 12 '16 at 20:02
@JonSkeet Sorry, I mean the offset in that specific moment in which the code is being executed. Between that timezone and UTC. — Axel Prieto, Oct 12 '16 at 20:04

Jon Skeet · Accepted Answer · 2019-01-30T07:03:01.997

25

You need DateTimeZone.GetUtcOffset(Instant):

public static int ConvertFromTimeZoneToMinutesOffset(string timeZone, IClock clock)
{
    DateTimeZone zone = DateTimeZoneProviders.Tzdb[timeZone];
    Offset offset = zone.GetUtcOffset(clock.Now);
    return offset.Milliseconds / NodaConstants.MillisecondsPerMinute;
}

You could leave off the IClock parameter and instead use SystemClock.Instance in the method, but that leads to code which is harder to test.

edited Jan 30 '19 at 07:03

answered Oct 12 '16 at 20:06

Jon Skeet

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Thank you very much Mr Skeet. – Axel Prieto Oct 12 '16 at 20:07
2

@AxelPrieto: I've just edited it btw, as otherwise you'd end up having to cast the result to `int`. – Jon Skeet Oct 12 '16 at 20:08
I believe that should be NodaConstants (with an s), in case anyone gets an error. – Andy Jan 30 '19 at 01:28
For NodaTime 2.0 use `clock.GetCurrentInstant()` in place of `clock.Now` – Chris Halcrow Jun 22 '21 at 23:22

score -2 · Answer 2 · answered Oct 12 '16 at 19:19

-2

Use the DatePart() function on minutes.

answered Oct 12 '16 at 19:19

Jim Snyder

99
2
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That's not enough. I don't have a "DateTime", I have a TimeZone. And I need the minutes, so instead of "America/Buenos Aires" I need -90 (the offset in minutes) – Axel Prieto Oct 12 '16 at 19:25

Get offset minutes from timezone (string) with NodaTime

2 Answers2

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