The Inner Drive Extensible Architecture™—the Idea™

Demonstration: Time zones

The IDEA™ includes a fully-object-oriented, easy-to-integrate set of tools to allow you to use the Internet-standard tzinfo database—used throughout the world on millions of Unix computers—in your .NET apps.

Explore time zones

We've loaded 496 time zones for you to check out:

Choose a world region
Find the zone name
Current time
UTC Monday, April 22, 2019 4:14:22 PM UTC
Inner Drive HQ Monday, April 22, 2019 11:14:22 AM CDT
America/Chicago Monday, April 22, 2019 11:14:22 AM CDT

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If you want to use the IDEA™ in your commercial application, check out our licensing options.

How this works

The time zone handling classes are in the InnerDrive.Geography assembly. Most are internal to the assembly; generally, you only need to work with the TimeZoneFactory class. The factory parses the raw tzinfo database and makes it available through a singleton instance.

First, the App.config or Web.config file (or wherever you store app settings) needs the following keys:

<?xml version="1.0"?>
<configuration xmlns="">
      <add key="DefaultTimeZoneRuleFile" value="C:\Source\InnerDrive\Utilities\tzinfo database\northamerica"/>
      <add key="DefaultTimeZoneHomeZone" value="America/Chicago"/>
      <add key="TimeZoneRuleFolder" value="C:\Source\InnerDrive\Utilities\tzinfo database"/>
      <add key="TimeZoneRuleFileFull" value="europe,northAmerica,pacificnew,southamerica,
		africa,antarctica,asia,australasia,backward,etcetera,leapseconds,solar87" />

At application start, the factory initializes. The Application_Start event handler calls this method:

private static void LoadTimeZones()
   var fileSpecListRaw = ConfigurationManager.AppSettings[TimeZoneFactory.DefaultTimeZoneRuleFileListSettingKey];
   var fileSpecList = fileSpecListRaw.Split(',');
   var dataFolder = ConfigurationManager.AppSettings[TimeZoneFactory.DefaultTimeZoneRuleFolderSettingKey];
      TimeZoneFactory.Instance.LoadTzInfoFiles(dataFolder, fileSpecList);
   catch (InvalidTimeZoneException itex)
      // log the exception
   // other exceptions elided

(By default, the factory will not throw an exception if a time zone definition is corrupt. The time zone will be unavaliable, however.)

At this point, you can use the default time zone—on this site, "America/Chicago", UTC-05:00—in one method call:

var thisZone = TimeZoneFactory.DefaultTimeZone;
var localTime = thisZone.ToLocalTime(DateTimeOffset.UtcNow);

Using a different zone is almost that easy. You simply call the TimeZoneFactory.FindZone method with the name of the zone you want. Here's the code from this page's code-behind:

private void SetLocalTime()
   var localZone = SelectedZone;
   resultPrompt.Text = localZone.Name;
   SetText(localZone, resultText);

private void SetText(IdtTimeZone timeZone, ITextControl control)
   var currentInfo = timeZone.CurrentInfo(SelectedTime);
   control.Text = string.Format(CultureInfo.CurrentCulture, "{0:D} {0:T} {1}",

Behind the scenes, time zone information is cached, making lookups very fast, and saving the trouble (and computing resources) of loading the tzinfo database again.

More information

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InnerDrive.Geography 3.2.6614.0 Release CLR 4.0.30319.42000
Copyright ©2018 Inner Drive Technology. All rights reserved. Portions Copyright ©1986-2018 David Braverman.

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Copyright ©2019 Inner Drive Technology. Purveyors of fine, hand-crafted computer software. Legal information. Page printed 2019-04-22T16:14:22 UTC.