DateTime.ToUniversalTime Method

Definition

Converte o valor do atual objeto DateTime em UTC (Tempo Universal Coordenado).Converts the value of the current DateTime object to Coordinated Universal Time (UTC).

public:
 DateTime ToUniversalTime();
public DateTime ToUniversalTime ();
member this.ToUniversalTime : unit -> DateTime
Public Function ToUniversalTime () As DateTime

Returns

DateTime

Um objeto cuja propriedade Kind é Utc, e cujo valor é o UTC equivalente ao valor do atual objeto DateTime, ou MaxValue se o valor convertido for muito grande para ser representado por um objeto DateTime, ou MinValue se o valor convertido for muito pequeno para ser representado por um objeto DateTime.An object whose Kind property is Utc, and whose value is the UTC equivalent to the value of the current DateTime object, or MaxValue if the converted value is too large to be represented by a DateTime object, or MinValue if the converted value is too small to be represented by a DateTime object.

Examples

O exemplo a seguir demonstra o método ToUniversalTime.The following example demonstrates the ToUniversalTime method.

using namespace System;

void main()
{
   Console::WriteLine("Enter a date and time.");
   String^ strDateTime = Console::ReadLine();

   DateTime localDateTime, univDateTime;
   try
   {
      localDateTime = DateTime::Parse(strDateTime);
      univDateTime = localDateTime.ToUniversalTime();
    
      Console::WriteLine("{0} local time is {1} universal time.",
                         localDateTime, univDateTime );
   }
   catch (FormatException^) 
   {
      Console::WriteLine("Invalid format.");
      return;
   }

   Console::WriteLine("Enter a date and time in universal time.");
   strDateTime = Console::ReadLine();

   try
   {
      univDateTime = DateTime::Parse(strDateTime);
      localDateTime = univDateTime.ToLocalTime();
  
      Console::WriteLine("{0} universal time is {1} local time.",
                         univDateTime, localDateTime );
   }
   catch (FormatException^) 
   {
      Console::WriteLine("Invalid format.");
      return;
   }
}
// The example displays output like the following when run on a 
// computer whose culture is en-US in the Pacific Standard Time zone:
//     Enter a date and time.
//     12/10/2015 6:18 AM
//     12/10/2015 6:18:00 AM local time is 12/10/2015 2:18:00 PM universal time.
//     Enter a date and time in universal time.
//     12/20/2015 6:42:00
//     12/20/2015 6:42:00 AM universal time is 12/19/2015 10:42:00 PM local time.
using System;

class Example
{
    static void Main()
    {
        DateTime localDateTime, univDateTime;
        
        Console.WriteLine("Enter a date and time.");
        string strDateTime = Console.ReadLine();

        try {
            localDateTime = DateTime.Parse(strDateTime);
            univDateTime = localDateTime.ToUniversalTime();

            Console.WriteLine("{0} local time is {1} universal time.",
                                localDateTime,
                                    univDateTime);
        }
        catch (FormatException) {
            Console.WriteLine("Invalid format.");
            return;
        }

        Console.WriteLine("Enter a date and time in universal time.");
        strDateTime = Console.ReadLine();

        try {
            univDateTime = DateTime.Parse(strDateTime);
            localDateTime = univDateTime.ToLocalTime();

            Console.WriteLine("{0} universal time is {1} local time.",
                                     univDateTime,
                                     localDateTime);
        }
        catch (FormatException) {
            Console.WriteLine("Invalid format.");
            return;
        }
    }
}
// The example displays output like the following when run on a
// computer whose culture is en-US in the Pacific Standard Time zone:
//     Enter a date and time.
//     12/10/2015 6:18 AM
//     12/10/2015 6:18:00 AM local time is 12/10/2015 2:18:00 PM universal time.
//     Enter a date and time in universal time.
//     12/20/2015 6:42:00
//     12/20/2015 6:42:00 AM universal time is 12/19/2015 10:42:00 PM local time.
Module Example
    Sub Main()
      Dim localDateTime, univDateTime As DateTime
      
      Console.WriteLine("Enter a date and time.")
      Dim strDateTime As String = Console.ReadLine()
      Try
         localDateTime = DateTime.Parse(strDateTime)
         univDateTime = localDateTime.ToUniversalTime()
         Console.WriteLine("{0} local time is {1} universal time.", 
                           localDateTime, univDateTime)
      Catch exp As FormatException
         Console.WriteLine("Invalid format.")
      End Try

      Console.WriteLine("Enter a date and time in universal time.")
      strDateTime = Console.ReadLine()
      Try
         univDateTime = DateTime.Parse(strDateTime)
         localDateTime = univDateTime.ToLocalTime()
  
         Console.WriteLine("{0} universal time is {1} local time.", _
                           univDateTime, localDateTime)
      Catch exp As FormatException
         Console.WriteLine("Invalid format.")
      End Try
    End Sub
End Module
' The example displays output like the following when run on a 
' computer whose culture is en-US in the Pacific Standard Time zone:
'     Enter a date and time.
'     12/10/2015 6:18 AM
'     12/10/2015 6:18:00 AM local time is 12/10/2015 2:18:00 PM universal time.
'     Enter a date and time in universal time.
'     12/20/2015 6:42:00
'     12/20/2015 6:42:00 AM universal time is 12/19/2015 10:42:00 PM local time.

O exemplo a seguir usa o método SpecifyKind para demonstrar como a propriedade Kind influencia os métodos de conversão ToLocalTime e ToUniversalTime.The following example uses the SpecifyKind method to demonstrate how the Kind property influences the ToLocalTime and ToUniversalTime conversion methods.

// This code example demonstrates the DateTime Kind, Now, and
// UtcNow properties, and the SpecifyKind(), ToLocalTime(),
// and ToUniversalTime() methods.

using System;

class Sample
{
    public static void Main()
    {
// Get the date and time for the current moment, adjusted
// to the local time zone.

    DateTime saveNow = DateTime.Now;

// Get the date and time for the current moment expressed
// as coordinated universal time (UTC).

    DateTime saveUtcNow = DateTime.UtcNow;
    DateTime myDt;

// Display the value and Kind property of the current moment
// expressed as UTC and local time.

    DisplayNow("UtcNow: ..........", saveUtcNow);
    DisplayNow("Now: .............", saveNow);
    Console.WriteLine();

// Change the Kind property of the current moment to
// DateTimeKind.Utc and display the result.

    myDt = DateTime.SpecifyKind(saveNow, DateTimeKind.Utc);
    Display("Utc: .............", myDt);

// Change the Kind property of the current moment to
// DateTimeKind.Local and display the result.

    myDt = DateTime.SpecifyKind(saveNow, DateTimeKind.Local);
    Display("Local: ...........", myDt);

// Change the Kind property of the current moment to
// DateTimeKind.Unspecified and display the result.

    myDt = DateTime.SpecifyKind(saveNow, DateTimeKind.Unspecified);
    Display("Unspecified: .....", myDt);
    }

// Display the value and Kind property of a DateTime structure, the
// DateTime structure converted to local time, and the DateTime
// structure converted to universal time.

    public static string datePatt = @"M/d/yyyy hh:mm:ss tt";
    public static void Display(string title, DateTime inputDt)
    {
    DateTime dispDt = inputDt;
    string dtString;

// Display the original DateTime.

    dtString = dispDt.ToString(datePatt);
    Console.WriteLine("{0} {1}, Kind = {2}",
                      title, dtString, dispDt.Kind);

// Convert inputDt to local time and display the result.
// If inputDt.Kind is DateTimeKind.Utc, the conversion is performed.
// If inputDt.Kind is DateTimeKind.Local, the conversion is not performed.
// If inputDt.Kind is DateTimeKind.Unspecified, the conversion is
// performed as if inputDt was universal time.

    dispDt = inputDt.ToLocalTime();
    dtString = dispDt.ToString(datePatt);
    Console.WriteLine("  ToLocalTime:     {0}, Kind = {1}",
                      dtString, dispDt.Kind);

// Convert inputDt to universal time and display the result.
// If inputDt.Kind is DateTimeKind.Utc, the conversion is not performed.
// If inputDt.Kind is DateTimeKind.Local, the conversion is performed.
// If inputDt.Kind is DateTimeKind.Unspecified, the conversion is
// performed as if inputDt was local time.

    dispDt = inputDt.ToUniversalTime();
    dtString = dispDt.ToString(datePatt);
    Console.WriteLine("  ToUniversalTime: {0}, Kind = {1}",
                      dtString, dispDt.Kind);
    Console.WriteLine();
    }

// Display the value and Kind property for DateTime.Now and DateTime.UtcNow.

    public static void DisplayNow(string title, DateTime inputDt)
    {
    string dtString = inputDt.ToString(datePatt);
    Console.WriteLine("{0} {1}, Kind = {2}",
                      title, dtString, inputDt.Kind);
    }
}

/*
This code example produces the following results:

UtcNow: .......... 5/6/2005 09:34:42 PM, Kind = Utc
Now: ............. 5/6/2005 02:34:42 PM, Kind = Local

Utc: ............. 5/6/2005 02:34:42 PM, Kind = Utc
  ToLocalTime:     5/6/2005 07:34:42 AM, Kind = Local
  ToUniversalTime: 5/6/2005 02:34:42 PM, Kind = Utc

Local: ........... 5/6/2005 02:34:42 PM, Kind = Local
  ToLocalTime:     5/6/2005 02:34:42 PM, Kind = Local
  ToUniversalTime: 5/6/2005 09:34:42 PM, Kind = Utc

Unspecified: ..... 5/6/2005 02:34:42 PM, Kind = Unspecified
  ToLocalTime:     5/6/2005 07:34:42 AM, Kind = Local
  ToUniversalTime: 5/6/2005 09:34:42 PM, Kind = Utc

*/

' This code example demonstrates the DateTime Kind, Now, and
' UtcNow properties, and the SpecifyKind(), ToLocalTime(), 
' and ToUniversalTime() methods.
Class Sample
    Public Shared Sub Main() 
        ' Get the date and time for the current moment, adjusted 
        ' to the local time zone.
        Dim saveNow As DateTime = DateTime.Now
        
        ' Get the date and time for the current moment expressed 
        ' as coordinated universal time (UTC).
        Dim saveUtcNow As DateTime = DateTime.UtcNow
        Dim myDt As DateTime
        
        ' Display the value and Kind property of the current moment 
        ' expressed as UTC and local time.
        DisplayNow("UtcNow: ..........", saveUtcNow)
        DisplayNow("Now: .............", saveNow)
        Console.WriteLine()
        
        ' Change the Kind property of the current moment to 
        ' DateTimeKind.Utc and display the result.
        myDt = DateTime.SpecifyKind(saveNow, DateTimeKind.Utc)
        Display("Utc: .............", myDt)
        
        ' Change the Kind property of the current moment to 
        ' DateTimeKind.Local and display the result.
        myDt = DateTime.SpecifyKind(saveNow, DateTimeKind.Local)
        Display("Local: ...........", myDt)
        
        ' Change the Kind property of the current moment to 
        ' DateTimeKind.Unspecified and display the result.
        myDt = DateTime.SpecifyKind(saveNow, DateTimeKind.Unspecified)
        Display("Unspecified: .....", myDt)
    End Sub
    
    ' Display the value and Kind property of a DateTime structure, the 
    ' DateTime structure converted to local time, and the DateTime 
    ' structure converted to universal time. 

    Public Shared datePatt As String = "M/d/yyyy hh:mm:ss tt"
    
    Public Shared Sub Display(ByVal title As String, ByVal inputDt As DateTime) 
        Dim dispDt As DateTime = inputDt
        Dim dtString As String
        
        ' Display the original DateTime.
        dtString = dispDt.ToString(datePatt)
        Console.WriteLine("{0} {1}, Kind = {2}", title, dtString, dispDt.Kind)
        
        ' Convert inputDt to local time and display the result. 
        ' If inputDt.Kind is DateTimeKind.Utc, the conversion is performed.
        ' If inputDt.Kind is DateTimeKind.Local, the conversion is not performed.
        ' If inputDt.Kind is DateTimeKind.Unspecified, the conversion is 
        ' performed as if inputDt was universal time.
        dispDt = inputDt.ToLocalTime()
        dtString = dispDt.ToString(datePatt)
        Console.WriteLine("  ToLocalTime:     {0}, Kind = {1}", dtString, dispDt.Kind)
        
        ' Convert inputDt to universal time and display the result. 
        ' If inputDt.Kind is DateTimeKind.Utc, the conversion is not performed.
        ' If inputDt.Kind is DateTimeKind.Local, the conversion is performed.
        ' If inputDt.Kind is DateTimeKind.Unspecified, the conversion is 
        ' performed as if inputDt was local time.
        dispDt = inputDt.ToUniversalTime()
        dtString = dispDt.ToString(datePatt)
        Console.WriteLine("  ToUniversalTime: {0}, Kind = {1}", dtString, dispDt.Kind)
        Console.WriteLine()
    End Sub
    
    
    ' Display the value and Kind property for DateTime.Now and DateTime.UtcNow.

    Public Shared Sub DisplayNow(ByVal title As String, ByVal inputDt As DateTime) 
        Dim dtString As String = inputDt.ToString(datePatt)
        Console.WriteLine("{0} {1}, Kind = {2}", title, dtString, inputDt.Kind)
    End Sub
End Class

'
'This code example produces the following results:
'
'UtcNow: .......... 5/6/2005 09:34:42 PM, Kind = Utc
'Now: ............. 5/6/2005 02:34:42 PM, Kind = Local
'
'Utc: ............. 5/6/2005 02:34:42 PM, Kind = Utc
'  ToLocalTime:     5/6/2005 07:34:42 AM, Kind = Local
'  ToUniversalTime: 5/6/2005 02:34:42 PM, Kind = Utc
'
'Local: ........... 5/6/2005 02:34:42 PM, Kind = Local
'  ToLocalTime:     5/6/2005 02:34:42 PM, Kind = Local
'  ToUniversalTime: 5/6/2005 09:34:42 PM, Kind = Utc
'
'Unspecified: ..... 5/6/2005 02:34:42 PM, Kind = Unspecified
'  ToLocalTime:     5/6/2005 07:34:42 AM, Kind = Local
'  ToUniversalTime: 5/6/2005 09:34:42 PM, Kind = Utc
'

Remarks

O UTC (tempo Universal Coordenado) é igual ao horário local menos o deslocamento UTC.The Coordinated Universal Time (UTC) is equal to the local time minus the UTC offset. Para obter mais informações sobre o deslocamento UTC, consulte TimeZone.GetUtcOffset.For more information about the UTC offset, see TimeZone.GetUtcOffset. A conversão também leva em conta a regra de horário de verão que se aplica à hora representada pelo objeto de DateTime atual.The conversion also takes into account the daylight saving time rule that applies to the time represented by the current DateTime object.

Important

Em sistemas Windows XPWindows XP, o método ToUniversalTime reconhece apenas a regra de ajuste atual ao converter de hora local em UTC.On Windows XPWindows XP systems, the ToUniversalTime method recognizes only the current adjustment rule when converting from local time to UTC. Como resultado, as conversões de períodos antes da regra de ajuste atual entraram em vigor podem não refletir com precisão a diferença entre a hora local e a UTC.As a result, conversions for periods before the current adjustment rule came into effect may not accurately reflect the difference between local time and UTC.

Começando com a versão 2,0 do .NET Framework, o valor retornado pelo método ToUniversalTime é determinado pela propriedade Kind do objeto de DateTime atual.Starting with the .NET Framework version 2.0, the value returned by the ToUniversalTime method is determined by the Kind property of the current DateTime object. A tabela a seguir descreve os possíveis resultados.The following table describes the possible results.

TipoKind ResultadosResults
Utc Nenhuma conversão é executada.No conversion is performed.
Local O objeto de DateTime atual é convertido em UTC.The current DateTime object is converted to UTC.
Unspecified O objeto de DateTime atual é considerado uma hora local e a conversão é executada como se Kind fosse Local.The current DateTime object is assumed to be a local time, and the conversion is performed as if Kind were Local.

Note

O método ToUniversalTime converte um valor de DateTime de hora local em UTC.The ToUniversalTime method converts a DateTime value from local time to UTC. Para converter a hora em um fuso horário não local em UTC, use o método TimeZoneInfo.ConvertTimeToUtc(DateTime, TimeZoneInfo).To convert the time in a non-local time zone to UTC, use the TimeZoneInfo.ConvertTimeToUtc(DateTime, TimeZoneInfo) method. Para converter uma hora cujo deslocamento do UTC é conhecido, use o método ToUniversalTime.To convert a time whose offset from UTC is known, use the ToUniversalTime method.

Se o valor de instância de data e hora for ambíguo, esse método assumirá que ele é um horário padrão.If the date and time instance value is an ambiguous time, this method assumes that it is a standard time. (Uma hora ambígua é aquela que pode ser mapeada para um horário padrão ou para um horário de verão no fuso horário local) Se o valor da instância de data e hora for uma hora inválida, esse método simplesmente subtrairá a hora local do deslocamento UTC do fuso horário local para retornar UTC.(An ambiguous time is one that can map either to a standard time or to a daylight saving time in the local time zone) If the date and time instance value is an invalid time, this method simply subtracts the local time from the local time zone's UTC offset to return UTC. (Uma hora inválida é aquela que não existe devido ao aplicativo das regras de ajuste de horário de verão.)(An invalid time is one that does not exist because of the application of daylight saving time adjustment rules.)

Notes to Callers

O método ToUniversalTime(), às vezes, é usado para converter uma hora local em UTC.The ToUniversalTime() method is sometimes used to convert a local time to UTC. O método ToLocalTime() é chamado para restaurar a hora local original.The ToLocalTime() method is then called to restore the original local time. No entanto, se a hora original representar uma hora inválida no fuso horário local, os dois valores de hora local não serão iguais.However, if the original time represents an invalid time in the local time zone, the two local time values will not be equal. Para obter informações adicionais e um exemplo, consulte o método ToLocalTime().For additional information and an example, see the ToLocalTime() method.

Em sistemas Windows XPWindows XP, o método ToUniversalTime() reconhece apenas a regra de ajuste atual para o fuso horário local, que se aplica a todas as datas, incluindo datas de nível inferior (ou seja, datas anteriores à data de início da regra de ajuste atual).On Windows XPWindows XP systems, the ToUniversalTime() method recognizes only the current adjustment rule for the local time zone, which it applies to all dates, including down-level dates (that is, dates that are earlier than the starting date of the current adjustment rule). Os aplicativos executados em Windows XPWindows XP que exigem cálculos de data e hora locais precisos de forma histórica devem contornar esse comportamento usando o método FindSystemTimeZoneById(String) para recuperar um objeto TimeZoneInfo que corresponda ao fuso horário local e chamar seu método ConvertTimeToUtc(DateTime, TimeZoneInfo).Applications running on Windows XPWindows XP that require historically accurate local date and time calculations must work around this behavior by using the FindSystemTimeZoneById(String) method to retrieve a TimeZoneInfo object that corresponds to the local time zone and calling its ConvertTimeToUtc(DateTime, TimeZoneInfo) method.

O exemplo a seguir ilustra a diferença entre os métodos ToUniversalTime() e ConvertTimeToUtc(DateTime, TimeZoneInfo) em um sistema Windows XPWindows XP no fuso horário do Pacífico americano.The following example illustrates the difference between the ToUniversalTime() and ConvertTimeToUtc(DateTime, TimeZoneInfo) methods on a Windows XPWindows XP system in the U.S. Pacific Time zone. As duas primeiras chamadas de método aplicam a regra de ajuste de fuso horário atual (que entrou em vigor em 2007) em uma data em 2006.The first two method calls apply the current time zone adjustment rule (which went into effect in 2007) to a date in 2006. A regra de ajuste atual fornece a transição para o horário de verão no segundo domingo de março; a regra anterior, que estava em vigor no 2006, foi fornecida para que a transição para o horário de verão ocorra no primeiro domingo de abril.The current adjustment rule provides for the transition to daylight saving time on the second Sunday of March; the previous rule, which was in effect in 2006, provided for the transition to daylight saving time to occur on the first Sunday of April. Somente a terceira chamada de método executa com precisão essa conversão de data e hora histórica.Only the third method call accurately performs this historical date and time conversion.

[! Code-CsharpSystem. DateTime. Parauniversaltime # 1] [! Code-VBSystem. DateTime. Parauniversaltime # 1][!code-csharpSystem.DateTime.ToUniversalTime#1] [!code-vbSystem.DateTime.ToUniversalTime#1]

Applies to

See also