DateTimeExtensions - C#

public static class DateTimeExtensions
{
    /// <summary>
    /// Returns a DateTimeOffset object of a specified date in a specified time zone
    /// </summary>
    /// <param name="dt">The date</param>
    /// <param name="timeZoneName">The name of the time zone. MUST be one of the
    /// [Id] values from the TimeZoneInfo.GetSystemTimeZones() method call.</param>
    /// <returns></returns>
    public static DateTimeOffset SpecifyTimeZone(this DateTime dt, string timeZoneName)
    {
        var tzi = TimeZoneInfo.FindSystemTimeZoneById(timeZoneName);
        return new DateTimeOffset(dt, tzi.GetUtcOffset(dt));
    }
}