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TimeZone.GetUtcOffset Method

Returns the coordinated universal time (UTC) offset for the specified local time.

[Visual Basic]
Public MustOverride Function GetUtcOffset( _
   ByVal time As DateTime _
) As TimeSpan
[C#]
public abstract TimeSpan GetUtcOffset(
 DateTime time
);
[C++]
public: virtual TimeSpan GetUtcOffset(
 DateTime time
) = 0;
[JScript]
public abstract function GetUtcOffset(
   time : DateTime
) : TimeSpan;

Parameters

time
The local date and time.

Return Value

The UTC offset from time, measured in ticks.

Remarks

Coordinated universal time (UTC) was previously known as Greenwich Mean Time (GMT). Local time is the date and time on the computer you are using. Offset is the difference between local time and UTC. That is:

local time = UTC + offset

time must be in the Gregorian calendar and the time zone represented by this instance. If time is in daylight saving time, this method returns the UTC offset to the daylight saving time zone. This method obtains the daylight saving time rule from the system.

For example, in the United States Pacific Standard time zone, which has -8 hours of offset, GetUtcOffset(new DateTime(1999, 1, 1)) returns -288000000000.

Example

[Visual Basic, C#, C++] The following code example uses the GetUtcOffset method to return the Coordinated Universal Time (UTC) offset for several local times.

[Visual Basic] 
' Example of the TimeZone.ToLocalTime( DateTime ) and 
' TimeZone.GetUtcOffset( DateTime ) methods.
Imports System
Imports Microsoft.VisualBasic

Module UTCTimeDemo

    Sub Main( )

        Const headFmt As String = "{0,-20}{1,-20}{2,-12}{3}"

        ' Get the local time zone and a base Coordinated Universal 
        ' Time (UTC).
        Dim localZone As TimeZone = TimeZone.CurrentTimeZone
        Dim baseUTC As DateTime = new DateTime( 2000, 1, 1 )

        Console.WriteLine( "This example of " & vbCrLf & _
            "   TimeZone.ToLocalTime( DateTime ) and" & vbCrLf & _
            "   TimeZone.GetUtcOffset( DateTime ) " & vbCrLf & _
            "generates the following output, which varies " & _
            "depending on the time zone " & vbCrLf & "in which " & _
            "it is run. The example creates several Coordinated " & _
            "Universal " & vbCrLf & "Times (UTC), displays the " & _
            "corresponding local times and UTC offsets, " & _
            vbCrLf & "and shows if the times occur in daylight " & _
            "saving time (DST)." & vbCrLf )
        Console.WriteLine( "Local time: {0}" & vbCrLf, _
            localZone.StandardName )

        Console.WriteLine( headFmt, "UTC", "Local Time", _
            " Offset", "DST?" )
        Console.WriteLine( headFmt, "---", "----------", _
            " ------", "----" )

        ' Generate several UTC times.
        Dim loopX As Integer
        For loopX = 0 to 10

            ' Calculate the local time and UTC offset.
            Dim localTime As DateTime = _
                localZone.ToLocalTime( baseUTC )
            Dim localOffset As TimeSpan = _
                localZone.GetUtcOffset( localTime )

            Console.WriteLine( "{0,-20:yyyy-MM-dd HH:mm}" & _
                "{1,-20:yyyy-MM-dd HH:mm}{2,-12}{3}", _
                baseUTC, localTime, localOffset, _
                localZone.IsDaylightSavingTime( localTime ) )
            
            ' Advance to another UTC.
            baseUTC = baseUTC.AddDays( 155.55 )
        Next loopX
    End Sub 
End Module 

' This example of
'    TimeZone.ToLocalTime( DateTime ) and
'    TimeZone.GetUtcOffset( DateTime )
' generates the following output, which varies depending on the time zone
' in which it is run. The example creates several Coordinated Universal
' Times (UTC), displays the corresponding local times and UTC offsets,
' and shows if the times occur in daylight saving time (DST).
' 
' Local time: Pacific Standard Time
' 
' UTC                 Local Time           Offset     DST?
' ---                 ----------           ------     ----
' 2000-01-01 00:00    1999-12-31 16:00    -08:00:00   False
' 2000-06-04 13:12    2000-06-04 06:12    -07:00:00   True
' 2000-11-07 02:24    2000-11-06 18:24    -08:00:00   False
' 2001-04-11 15:36    2001-04-11 08:36    -07:00:00   True
' 2001-09-14 04:48    2001-09-13 21:48    -07:00:00   True
' 2002-02-16 18:00    2002-02-16 10:00    -08:00:00   False
' 2002-07-22 07:12    2002-07-22 00:12    -07:00:00   True
' 2002-12-24 20:24    2002-12-24 12:24    -08:00:00   False
' 2003-05-29 09:36    2003-05-29 02:36    -07:00:00   True
' 2003-10-31 22:48    2003-10-31 14:48    -08:00:00   False
' 2004-04-04 12:00    2004-04-04 05:00    -07:00:00   True

[C#] 
// Example of the TimeZone.ToLocalTime( DateTime ) and 
// TimeZone.GetUtcOffset( DateTime ) methods.
using System;

class UTCTimeDemo
{
    static void Main( )
    {
        const string headFmt = "{0,-20}{1,-20}{2,-12}{3}";

        // Get the local time zone and a base Coordinated Universal 
        // Time (UTC).
        TimeZone localZone = TimeZone.CurrentTimeZone;
        DateTime baseUTC = new DateTime( 2000, 1, 1 );

        Console.WriteLine( "This example of \n" +
            "   TimeZone.ToLocalTime( DateTime ) and\n" +
            "   TimeZone.GetUtcOffset( DateTime ) \ngenerates the " +
            "following output, which varies depending on the time " +
            "zone \nin which it is run. The example creates several " +
            "Coordinated Universal \nTimes (UTC), displays the " +
            "corresponding local times and UTC offsets, \nand shows " +
            "if the times occur in daylight saving time (DST)." );
        Console.WriteLine( "\nLocal time: {0}\n", 
            localZone.StandardName );

        Console.WriteLine( headFmt, "UTC", "Local Time", 
            " Offset", "DST?" );
        Console.WriteLine( headFmt, "---", "----------", 
            " ------", "----" );

        // Generate several UTC times.
        for( int loopX = 0; loopX <= 10; loopX++ )
        {
            // Calculate the local time and UTC offset.
            DateTime localTime = localZone.ToLocalTime( baseUTC );
            TimeSpan localOffset = 
                localZone.GetUtcOffset( localTime );

            Console.WriteLine( "{0,-20:yyyy-MM-dd HH:mm}" +
                "{1,-20:yyyy-MM-dd HH:mm}{2,-12}{3}", 
                baseUTC, localTime, localOffset, 
                localZone.IsDaylightSavingTime( localTime ) );
            
            // Advance to another UTC.
            baseUTC = baseUTC.AddDays( 155.55 );
        }
    } 
} 

/*
This example of
   TimeZone.ToLocalTime( DateTime ) and
   TimeZone.GetUtcOffset( DateTime )
generates the following output, which varies depending on the time zone
in which it is run. The example creates several Coordinated Universal
Times (UTC), displays the corresponding local times and UTC offsets,
and shows if the times occur in daylight saving time (DST).

Local time: Pacific Standard Time

UTC                 Local Time           Offset     DST?
---                 ----------           ------     ----
2000-01-01 00:00    1999-12-31 16:00    -08:00:00   False
2000-06-04 13:12    2000-06-04 06:12    -07:00:00   True
2000-11-07 02:24    2000-11-06 18:24    -08:00:00   False
2001-04-11 15:36    2001-04-11 08:36    -07:00:00   True
2001-09-14 04:48    2001-09-13 21:48    -07:00:00   True
2002-02-16 18:00    2002-02-16 10:00    -08:00:00   False
2002-07-22 07:12    2002-07-22 00:12    -07:00:00   True
2002-12-24 20:24    2002-12-24 12:24    -08:00:00   False
2003-05-29 09:36    2003-05-29 02:36    -07:00:00   True
2003-10-31 22:48    2003-10-31 14:48    -08:00:00   False
2004-04-04 12:00    2004-04-04 05:00    -07:00:00   True
*/ 

[C++] 
// Example of the TimeZone::ToLocalTime( DateTime ) and 
// TimeZone::GetUtcOffset( DateTime ) methods.
#using <mscorlib.dll>
using namespace System;

void main( )
{
    String* headFmt = S"{0,-20}{1,-20}{2,-12}{3}";

    // Get the local time zone and a base Coordinated Universal 
    // Time (UTC).
    TimeZone* localZone = TimeZone::CurrentTimeZone;
    DateTime  baseUTC = DateTime( 2000, 1, 1 );

    Console::WriteLine( S"This example of \n" 
        S"   TimeZone::ToLocalTime( DateTime ) and\n" 
        S"   TimeZone::GetUtcOffset( DateTime ) \ngenerates the " 
        S"following output, which varies depending on the time " 
        S"zone \nin which it is run. The example creates several " 
        S"Coordinated Universal \nTimes (UTC), displays the " 
        S"corresponding local times and UTC offsets, \nand shows " 
        S"if the times occur in daylight saving time (DST)." );
    Console::WriteLine( S"\nLocal time: {0}\n", 
        localZone->StandardName );

    Console::WriteLine( headFmt, S"UTC", S"Local Time", 
        S" Offset", S"DST?" );
    Console::WriteLine( headFmt, S"---", S"----------", 
        S" ------", S"----" );

    // Generate several UTC times.
    for( int loopX = 0; loopX <= 10; loopX++ )
    {
        // Calculate the local time and UTC offset.
        DateTime localTime = localZone->ToLocalTime( baseUTC );
        TimeSpan localOffset = 
            localZone->GetUtcOffset( localTime );

        Console::WriteLine( S"{0,-20:yyyy-MM-dd HH:mm}" 
            S"{1,-20:yyyy-MM-dd HH:mm}{2,-12}{3}", 
            __box( baseUTC ), __box( localTime ), 
            __box( localOffset ), 
            __box( localZone->IsDaylightSavingTime( localTime ) ) );
        
        // Advance to another UTC.
        baseUTC = baseUTC.AddDays( 155.55 );
    }
} 

/*
This example of
   TimeZone::ToLocalTime( DateTime ) and
   TimeZone::GetUtcOffset( DateTime )
generates the following output, which varies depending on the time zone
in which it is run. The example creates several Coordinated Universal
Times (UTC), displays the corresponding local times and UTC offsets,
and shows if the times occur in daylight saving time (DST).

Local time: Pacific Standard Time

UTC                 Local Time           Offset     DST?
---                 ----------           ------     ----
2000-01-01 00:00    1999-12-31 16:00    -08:00:00   False
2000-06-04 13:12    2000-06-04 06:12    -07:00:00   True
2000-11-07 02:24    2000-11-06 18:24    -08:00:00   False
2001-04-11 15:36    2001-04-11 08:36    -07:00:00   True
2001-09-14 04:48    2001-09-13 21:48    -07:00:00   True
2002-02-16 18:00    2002-02-16 10:00    -08:00:00   False
2002-07-22 07:12    2002-07-22 00:12    -07:00:00   True
2002-12-24 20:24    2002-12-24 12:24    -08:00:00   False
2003-05-29 09:36    2003-05-29 02:36    -07:00:00   True
2003-10-31 22:48    2003-10-31 14:48    -08:00:00   False
2004-04-04 12:00    2004-04-04 05:00    -07:00:00   True
*/ 

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, .NET Compact Framework

See Also

TimeZone Class | TimeZone Members | System Namespace

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