convert utc time and offset to DateTime

Question

i have a datetime(in utc) saved in database and i also know the utc offset in the following format.

-03:00:00

how to convert this to a DateTime

`12:12:12` does not look like a UTC offset to me, or a `datetime` field either. Can you elaborate on the meaning of each part? — Oded, Jul 29 '10 at 11:17
http://stackoverflow.com/questions/2548235/convert-utc-datetime-to-another-time-zone this will help you — Aykut Çevik, Jul 29 '10 at 11:18
@Oded it is the utc offset. it's range is -12:00:00 to 13:00:00 — developer, Jul 29 '10 at 11:24

score 17 · Answer 1 · answered Jul 29 '10 at 11:59

17

This simplest way to apply an "offset" to a DateTime that you already have is to create a TimeSpan structure which holds your offset value, and then simply "add" the offset to the original DateTime value.

For example:

DateTime utcDateTime = DateTime.Parse("29 July 2010 14:13:45");
TimeSpan offSet = TimeSpan.Parse("-03:00:00");
DateTime newDateTime = utcDateTime + offSet;
Console.WriteLine(newDateTime);

This results in the following output:

29/07/2010 11:13:45

which is the original time (29 July 2010 14:13:45) minus 3 hours (the offset - -03:00:00).

Note that this technique is merely performing simple arithmetic with your DateTime value and does not take any time zones into account.

answered Jul 29 '10 at 11:59

CraigTP

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Note that the Parse fails when you have the '+' sign in the string. So use the '-' sign or no sign at all! http://msdn.microsoft.com/en-us/library/se73z7b9%28v=vs.110%29.aspx – Jowen Jan 14 '15 at 14:22
What about daylight saving? – Anil Purswani Feb 12 '16 at 12:51
@AnilPurswani You would only be able to apply daylight savings offset if you know the specific timezone rather than just an "hours offset". The TimeZoneInfo class has a property (SupportsDaylightSavingTime) to indicate if a specific timezone supports daylight savings. Different timezones may have the same hours offset but may or may not support daylight savings. – CraigTP Feb 12 '16 at 12:56

score 0 · Answer 2 · answered May 30 '11 at 05:07

The problem you are likely running into is that most DB drivers when fetching from the database will create the DateTime with DateTimeKind.Unspecified, which may not convert to UTC properly even when you use ToUniversalTime. To get arround this I use an extension method like this:

    public static DateTime ToSafeUniversalTime(this DateTime date) {
        if(date != DateTime.MinValue && date != DateTime.MaxValue) {
            switch(date.Kind) {
            case DateTimeKind.Unspecified:
                date = new DateTime(date.Year, date.Month, date.Day, date.Hour, date.Minute, date.Second, DateTimeKind.Utc);
                break;
            case DateTimeKind.Local:
                date = date.ToUniversalTime();
                break;
            }
        }
        return date;
    }

convert utc time and offset to DateTime

2 Answers2

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