How to tell if it's British Summer Time

Question

I have the following code, which should return an offset of 60 (to show that in the UK at present, we are in British Summer Time - ie. 60 minutes ahead of GMT):

Answer 1

To master conversion from one timezone to anther you need to see what's supported (how?) and what's not.

foreach (var tz in TimeZoneInfo.GetSystemTimeZones())
{
    Console.WriteLine("TimeZone Offset: {0} Name : {1}, Supports DLS: {2}", tz.BaseUtcOffset,tz.StandardName,tz.SupportsDaylightSavingTime);
}

This should give you the list all timezones including info about DayLightSaving. Notice that:

TimeZone Offset: 00:00:00 Name : Greenwich Standard Time, Supports DLS: False

TimeZone Offset: 00:00:00 Name : GMT Standard Time, Supports DLS: True

So you need to use "GMT Standard Time" because it supports daylight saving already. No work needs to be done.

Here is sample code:

private static string GetBSTTimeStamp(string timestamp)
{
    DateTime dt = DateTime.Parse(timestamp);
    //TimeZoneInfo bst = TimeZoneInfo.FindSystemTimeZoneById("GMT Standard Time");
    //Console.WriteLine("Time zone supports dls? {0}", bst.SupportsDaylightSavingTime);
    //Console.WriteLine("Time zone offset? {0}", bst.BaseUtcOffset);
    DateTime dateTimeInUtc = TimeZoneInfo.ConvertTimeBySystemTimeZoneId(dt, "Eastern Standard Time", "GMT Standard Time");
    return dateTimeInUtc.ToString();
}