TZ4Net Library

C# /.NET implementation of timezone class based on Olson database (often called tz or zoneinfo). As opposite to Win32/.NET API, it allows to perform conversion of arbitrary time between arbitrary time zones.

Key features:

• OlsonTimeZone class which subclasses System.TimeZone
• Leapsecond support
• Time validation against "spring forward" and "fall back" regions
• Unicode CLDR v.1.7.1 based mapping between Win32 Id and Olson name
• Multiple naming scheme: TZIDs, aliases, abbreviations, Win32 ids and names, military letters and names
• Latest version of tz package - 2009p
• Zone explorer in demo application to allow browsing timezone data
• 100% managed code
• ASP.NET hosting, No-touch and Click-once deployment friendly: no access to file system or registry needed
• Freeware

Important note for VS 2008 users : Project migrated to VS 2008 fails on accessing both embedded resource files. Workaround is to add additional .resources suffix to their names so they are named zoneinfo.resources.resources and cldrinfo.resources.resources accordingly.

using TZ4Net;

static DateTime Convert(DateTime srcTime, string srcName, string dstName)
{
  if (OlsonTimeZone.LookupName(srcName) == null)
  {
    throw new ArgumentException("Unknown source timezone name.");
  }
  if (OlsonTimeZone.LookupName(dstName) == null)
  {
    throw new ArgumentException("Unknown destintation timezone name.");
  }
  OlsonTimeZone srcZone = OlsonTimeZone.GetInstance(srcName);
  TimeCheckResult srcCheckRes = srcZone.CheckLocalTime(srcTime);
  switch (srcCheckRes)
  {
    case TimeCheckResult.Valid :
    {
      OlsonTimeZone dstZone = OlsonTimeZone.GetInstance(dstName);
      DateTime dstTime = dstZone.ToLocalTime(srcZone.ToUniversalTime(srcTime));
      return dstTime;
    }
    case TimeCheckResult.InSpringForwardGap :
    case TimeCheckResult.InFallBackRange :
    {
      throw new ArgumentException("Source time in transition period.");
    }
    default :
    {
      throw new ArgumentException("Source time out of range.");
    }
  }
}

using TZ4Net;

static ZoneInfo.Time Convert(ZoneInfo.Time srcTime, string srcName, string dstName)
{
  if (Array.IndexOf(ZoneInfo.GetAllNames("zoneinfo-leaps"), srcName) < 0)
  {
    throw new ArgumentException("Unknown source timezone name.");
  }
  if (Array.IndexOf(ZoneInfo.GetAllNames("zoneinfo-leaps"), dstName) < 0)
  {
    throw new ArgumentException("Unknown destintation timezone name.");
  }
  ZoneInfo srcZone = new ZoneInfo(srcName, "zoneinfo-leaps");
  ZoneInfo dstZone = new ZoneInfo(dstName, "zoneinfo-leaps");
  long srcClock = ZoneInfo.MinClock;
  try
  {
    srcClock = srcZone.GetClockFromLocal(srcTime);
  }
  catch (ArgumentException)
  {
    throw new ArgumentException("Invalid source time.");
  }
  return dstZone.GetLocalTime(srcClock);
}