C# TimeZone Examples

TimeZone describes the current time zone.

It gets information about the time zone of the current computer. Time zones on the planet Earth change on lines on longitude. You cannot assume a particular time zone.

Names. What is the name of a specific time zone? The .NET Framework contains information about the names for time zones. You can access the properties StandardName and DaylightName to get these strings.

Also: This example shows how to get the current time zone with the TimeZone.CurrentTimeZone property accessor.

C# program that gets time zone names

using System;

class Program
{
    static void Main()
    {
	// Get current time zone.
	TimeZone zone = TimeZone.CurrentTimeZone;
	string standard = zone.StandardName;
	string daylight = zone.DaylightName;
	Console.WriteLine(standard);
	Console.WriteLine(daylight);
    }
}

Output
    This will depend on your computer's location and system settings.

Mountain Standard Time
Mountain Daylight Time

Universal time. There are two concepts of time you can use. The local time depends on where the computer is located. The universal time is independent of this. With universal times, you can compare times from different locations with no errors.

C# program that checks universal and local times

using System;

class Program
{
    static void Main()
    {
	TimeZone zone =  TimeZone.CurrentTimeZone;
	// Demonstrate ToLocalTime and ToUniversalTime.
	DateTime local = zone.ToLocalTime(DateTime.Now);
	DateTime universal = zone.ToUniversalTime(DateTime.Now);
	Console.WriteLine(local);
	Console.WriteLine(universal);
    }
}

Output
    This also depends on your computer's location.

8/26/2014 1:02:28 PM
8/26/2014 7:02:28 PM

Get offsets. A UTC offset indicates how many hours a time zone differs from the Coordinated Universal Time. When you call GetUtcOffset on a TimeZone instance, you get a TimeSpan instance that indicates how many hours the time is different from UTC.

TimeSpan

Note: Coordinated Universal Time is also referred to as Zulu Time or Greenwich Mean Time.

C# program that checks UTC offset

using System;

class Program
{
    static void Main()
    {
	TimeZone zone = TimeZone.CurrentTimeZone;
	// Get offset.
	TimeSpan offset = zone.GetUtcOffset(DateTime.Now);
	Console.WriteLine(offset);
    }
}

Output
    Results vary on location.

-06:00:00

Daylight changes. Daylight saving time was invented by George Vernon Hudson in New Zealand. Its intention is to save money by reducing the costs of keeping lights on at night. Today, its main purpose is to make software programmers' lives hard.

Next: In this example, we get information about the current year's daylight saving changes.

C# program that shows daylight changes

using System;
using System.Globalization;

class Program
{
    static void Main()
    {
	// Get daylight saving information for current time zone.
	TimeZone zone = TimeZone.CurrentTimeZone;
	DaylightTime time = zone.GetDaylightChanges(DateTime.Today.Year);
	Console.WriteLine("Start: {0}", time.Start);
	Console.WriteLine("End: {0}", time.End);
	Console.WriteLine("Delta: {0}", time.Delta);
    }
}

Output
    Your mileage may vary.

Start: 3/14/2010 2:00:00 AM
End: 11/7/2010 2:00:00 AM
Delta: 01:00:00

Daylight saving time. This program scans individual dates for their daylight saving status. It is probably better to use the GetDaylightChanges method instead of the IsDaylightSavingTime method repeatedly. But IsDaylightSavingTime can be useful in some cases.

C# program that checks daylight saving time

using System;

class Program
{
    static void Main()
    {
	DateTime d = new DateTime(2010, 1, 1);
	TimeZone cur = TimeZone.CurrentTimeZone;
	bool flag = !cur.IsDaylightSavingTime(d);

	for (int i = 0; i < 365; i++)
	{
	    bool f = cur.IsDaylightSavingTime(d);
	    if (f != flag)
	    {
		Console.WriteLine("{0}: begin {1}", d, f);
		flag = f;
	    }
	    d = d.AddDays(1);
	}
    }
}

Output
    Depends on your time zone.

1/1/2010 12:00:00 AM: begin False
3/15/2010 12:00:00 AM: begin True
11/8/2010 12:00:00 AM: begin False

Summary. The TimeZone type in the C# language and .NET Framework provides a handy way to get information about time zones. We use the CurrentTimeZone property to get the information for the computer.

Then: We can call methods that reveal information about daylight saving time universal times and UTC offsets.

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