Convert some local time to UTC in C#

Question

I am trying do to something like this:

On a client side I have datepicker for selecting date, drop down for selecting an hour, and drop down with time zones for selecting user time zone.

I am sending this info to server. On a server side, I want to accomplish this:

Take date and time values, and check what is the value of time zone. If it is for example "UTC+1" (or any other +- value of UTC time), convert that into UTC, before saving.

What I am not sure how to do it is: What value should I send from client as time zone information so server can detect it is a for example UTC+1.

I saw examples like this:

TimeZoneInfo tz = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time");

On how to find out what is the time zone by its id, but I cannot do something like this:

TimeZoneInfo tz = TimeZoneInfo.FindSystemTimeZoneById("UTC+1");

Because, I get an exception, of course:

Additional information: The time zone ID 'UTC+1' was not found on the local computer.

Does someone know what is Id for all UTC+-someNumber, or there is a way to detect timezone from UTC string in some different way?

Did someone had experience whit this kind of a conversion?

You can get *all the time zones about which information is available on the local system* by calling `TimeZoneInfo.GetSystemTimeZones()` and check their `BaseUtcOffset`. Besides that, it might be simpler to calculate the UTC time on the client side, before sending it to the server. — Clemens, Nov 01 '16 at 11:14

score 1 · Answer 1 · edited May 23 '17 at 10:32

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As far as I remember the only way to work with the timezones is by the full name that is available in your OS.

You can find a similar question here.

A list from MSDN is here.

So there seems to be no easy way to convert strings like "UTC+1", unless you create a mapping to the ones that are supported by framework.

edited May 23 '17 at 10:32

Community

1
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answered Nov 01 '16 at 11:07

Ilya Chernomordik

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score 0 · Answer 2 · answered Nov 01 '16 at 11:16

You could use TimeZoneInfo.CreateCustomTimeZone():

DateTime utcTime = DateTime.UtcNow;
TimeZoneInfo targetTimeZone = TimeZoneInfo.CreateCustomTimeZone("MyId", TimeSpan.FromHours(1), "Somewhere", "Somewhere");
DateTime targetTime = TimeZoneInfo.ConvertTime(utcTime, targetTimeZone);

or you can use DateTimeOffset, or DateTime.AddHours(1):

var datetimeOffset = new DateTimeOffset(yourDateTime, TimeSpan.FromHours(1));
var otherDatetime = yourDateTime.AddHours(1);

Convert some local time to UTC in C#

2 Answers2