Creating a DateTime in a specific Time Zone in c#

Question

I'm trying to create a unit test to test the case for when the timezone changes on a machine because it has been incorrectly set and then corrected.

In the test I need to be able to create DateTime objects in a none local time zone to ensure that people running the test can do so successfully irrespective of where they are located.

From what I can see from the DateTime constructor I can set the TimeZone to be either the local timezone, the UTC timezone or not specified.

How do I create a DateTime with a specific timezone like PST?

Answer 1

Jon's answer talks about TimeZone, but I'd suggest using TimeZoneInfo instead.

Personally I like keeping things in UTC where possible (at least for the past; storing UTC for the future has potential issues), so I'd suggest a structure like this:

public struct DateTimeWithZone
{
    private readonly DateTime utcDateTime;
    private readonly TimeZoneInfo timeZone;

    public DateTimeWithZone(DateTime dateTime, TimeZoneInfo timeZone)
    {
        var dateTimeUnspec = DateTime.SpecifyKind(dateTime, DateTimeKind.Unspecified);
        utcDateTime = TimeZoneInfo.ConvertTimeToUtc(dateTimeUnspec, timeZone); 
        this.timeZone = timeZone;
    }

    public DateTime UniversalTime { get { return utcDateTime; } }

    public TimeZoneInfo TimeZone { get { return timeZone; } }

    public DateTime LocalTime
    { 
        get 
        { 
            return TimeZoneInfo.ConvertTime(utcDateTime, timeZone); 
        }
    }        
}

You may wish to change the "TimeZone" names to "TimeZoneInfo" to make things clearer - I prefer the briefer names myself.