How should I populate a list of IANA / Olson time zones from Noda Time?

Question

I am using NodaTime in an application, and I need the user to select their timezone from a dropdown list. I have the following soft requirements:

1) The list only c

Answer 1

Noda Time 1.1 has the zone.tab data, so you can now do the following:

/// 

/// Returns a list of valid timezones as a dictionary, where the key is
/// the timezone id, and the value can be used for display.
/// 
/// 
/// The two-letter country code to get timezones for.
/// Returns all timezones if null or empty.
/// 
public IDictionary GetTimeZones(string countryCode)
{
    var now = SystemClock.Instance.Now;
    var tzdb = DateTimeZoneProviders.Tzdb;

    var list = 
        from location in TzdbDateTimeZoneSource.Default.ZoneLocations
        where string.IsNullOrEmpty(countryCode) ||
              location.CountryCode.Equals(countryCode, 
                                          StringComparison.OrdinalIgnoreCase)
        let zoneId = location.ZoneId
        let tz = tzdb[zoneId]
        let offset = tz.GetZoneInterval(now).StandardOffset
        orderby offset, zoneId
        select new
        {
            Id = zoneId,
            DisplayValue = string.Format("({0:+HH:mm}) {1}", offset, zoneId)
        };

    return list.ToDictionary(x => x.Id, x => x.DisplayValue);
}

Alternative Approach

Instead of providing a drop down at all, you can use a map-based timezone picker.