DateTime.ToUniversalTime Metodo
Definizione
Importante
Alcune informazioni sono relative alla release non definitiva del prodotto, che potrebbe subire modifiche significative prima della release definitiva. Microsoft non riconosce alcuna garanzia, espressa o implicita, in merito alle informazioni qui fornite.
Converte il valore dell'oggetto DateTime corrente nell'ora UTC (Coordinated Universal Time).
public:
DateTime ToUniversalTime();public DateTime ToUniversalTime ();member this.ToUniversalTime : unit -> DateTimePublic Function ToUniversalTime () As DateTimeRestituisce
Oggetto la cui Kind proprietà è , e il cui valore è Utcl'utc equivalente al valore dell'oggetto corrente DateTime o DateTime.MaxValue se il valore convertito è troppo grande da rappresentare da un oggetto o DateTime.MinValue se il valore convertito è troppo piccolo da rappresentare da un DateTimeDateTime oggetto.
Esempio
Nell'esempio seguente viene illustrato il ToUniversalTime metodo.
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.
open System
printfn "Enter a date and time."
try
let strDateTime = stdin.ReadLine()
let localDateTime = DateTime.Parse strDateTime
let univDateTime = localDateTime.ToUniversalTime()
printfn $"{localDateTime} local time is {univDateTime} universal time."
with :? FormatException ->
printfn "Invalid format."
printfn "Enter a date and time in universal time."
try
let strDateTime = stdin.ReadLine()
let univDateTime = DateTime.Parse strDateTime
let localDateTime = univDateTime.ToLocalTime()
printfn $"{univDateTime} universal time is {localDateTime} local time."
with :? FormatException ->
printfn "Invalid format."
// 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.
Nell'esempio seguente viene usato il SpecifyKind metodo per illustrare come la Kind proprietà influisce sui ToLocalTime metodi di conversione e ToUniversalTime .
// This code example demonstrates the DateTime Kind, Now, and
// UtcNow properties, and the SpecifyKind(), ToLocalTime(),
// and ToUniversalTime() methods.
open System
// 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.
let datePatt = @"M/d/yyyy hh:mm:ss tt"
let display title (inputDt: DateTime) =
// Display the original DateTime.
let dispDt = inputDt
let dtString = dispDt.ToString datePatt
printfn $"%s{title} {dtString}, Kind = {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.
let dispDt = inputDt.ToLocalTime()
let dtString = dispDt.ToString datePatt
printfn $" ToLocalTime: {dtString}, Kind = {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.
let dispDt = inputDt.ToUniversalTime()
let dtString = dispDt.ToString datePatt
printfn $" ToUniversalTime: {dtString}, Kind = {dispDt.Kind}\n"
// Display the value and Kind property for DateTime.Now and DateTime.UtcNow.
let displayNow title (inputDt: DateTime) =
let dtString = inputDt.ToString datePatt
printfn $"%s{title} {dtString}, Kind = {inputDt.Kind}"
[<EntryPoint>]
let main _ =
// Get the date and time for the current moment, adjusted
// to the local time zone.
let saveNow = DateTime.Now
// Get the date and time for the current moment expressed
// as coordinated universal time (UTC).
let saveUtcNow = DateTime.UtcNow
// Display the value and Kind property of the current moment
// expressed as UTC and local time.
displayNow "UtcNow: .........." saveUtcNow
displayNow "Now: ............." saveNow
printfn ""
// Change the Kind property of the current moment to
// DateTimeKind.Utc and display the result.
let myDt = DateTime.SpecifyKind(saveNow, DateTimeKind.Utc)
display "Utc: ............." myDt
// Change the Kind property of the current moment to
// DateTimeKind.Local and display the result.
let myDt = DateTime.SpecifyKind(saveNow, DateTimeKind.Local)
display "Local: ..........." myDt
// Change the Kind property of the current moment to
// DateTimeKind.Unspecified and display the result.
let myDt = DateTime.SpecifyKind(saveNow, DateTimeKind.Unspecified)
display "Unspecified: ....." myDt
0
// 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.
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
'
Commenti
L'ora UTC (Coordinated Universal Time) è uguale all'ora locale meno l'offset UTC. Per altre informazioni sull'offset UTC, vedere TimeZoneInfo.GetUtcOffset. La conversione tiene conto anche della regola dell'ora legale che si applica all'ora rappresentata dall'oggetto corrente DateTime .
Importante
Nei sistemi Windows XP il ToUniversalTime metodo riconosce solo la regola di regolazione corrente durante la conversione dall'ora locale all'ora UTC. Di conseguenza, le conversioni per i periodi prima dell'entrata in vigore della regola di regolazione corrente potrebbero non riflettere in modo accurato la differenza tra ora locale e UTC.
A partire da .NET Framework versione 2.0, il valore restituito dal metodo è determinato dalla ToUniversalTimeKind proprietà dell'oggetto corrente DateTime . La tabella seguente descrive i possibili risultati.
| Tipo | Risultati |
|---|---|
| Utc | Non viene eseguita alcuna conversione. |
| Local | L'oggetto corrente DateTime viene convertito in UTC. |
| Unspecified | Si presuppone che l'oggetto corrente DateTime sia un'ora locale e la conversione venga eseguita come se Kind fosse Local. |
Nota
Il ToUniversalTime metodo converte un DateTime valore dall'ora locale all'ora UTC. Per convertire l'ora in un fuso orario non locale in formato UTC, usare il TimeZoneInfo.ConvertTimeToUtc(DateTime, TimeZoneInfo) metodo . Per convertire un'ora la cui offset da UTC è noto, usare il ToUniversalTime metodo .
Se il valore dell'istanza di data e ora è un'ora ambigua, questo metodo presuppone che sia un'ora standard. (Un'ora ambigua è una che può eseguire il mapping a un'ora standard o a un'ora legale nel fuso orario locale) Se il valore dell'istanza di data e ora è un'ora non valida, questo metodo sottrae semplicemente l'ora locale dall'offset UTC del fuso orario locale per restituire l'ora UTC. Un'ora non valida è una che non esiste a causa dell'applicazione delle regole di regolazione dell'ora legale.
Note per i chiamanti
Il ToUniversalTime() metodo viene talvolta usato per convertire un'ora locale in utc. Il ToLocalTime() metodo viene quindi chiamato per ripristinare l'ora locale originale. Tuttavia, se l'ora originale rappresenta un'ora non valida nel fuso orario locale, i due valori dell'ora locale non saranno uguali. Per altre informazioni e un esempio, vedere il ToLocalTime() metodo .
Nei sistemi Windows XP il ToUniversalTime() metodo riconosce solo la regola di regolazione corrente per il fuso orario locale, che si applica a tutte le date, incluse le date a livello inferiore, ovvero le date precedenti alla data di inizio della regola di regolazione corrente. Le applicazioni in esecuzione in Windows XP che richiedono calcoli cronologici di data e ora locali accurati devono aggirare questo comportamento usando il metodo per recuperare un TimeZoneInfo oggetto corrispondente al fuso orario locale e chiamare ConvertTimeToUtc(DateTime, TimeZoneInfo) il FindSystemTimeZoneById(String) relativo metodo.
Nell'esempio seguente viene illustrata la differenza tra i ToUniversalTime() metodi e ConvertTimeToUtc(DateTime, TimeZoneInfo) in un sistema Windows XP nel fuso orario pacifico degli Stati Uniti. Le prime due chiamate al metodo applicano la regola di regolazione del fuso orario corrente (che ha effetto nel 2007) a una data nel 2006. La regola di regolazione corrente prevede la transizione all'ora legale la seconda domenica di marzo; la regola precedente, che è stata applicata nel 2006, ha fornito la transizione all'ora legale per verificarsi la prima domenica di aprile. Solo la terza chiamata al metodo esegue in modo accurato questa conversione cronologica di data e ora.
using System;
public class Example
{
public static void Main()
{
DateTime date1 = new DateTime(2006, 3, 21, 2, 0, 0);
Console.WriteLine(date1.ToUniversalTime());
Console.WriteLine(TimeZoneInfo.ConvertTimeToUtc(date1));
TimeZoneInfo tz = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time");
Console.WriteLine(TimeZoneInfo.ConvertTimeToUtc(date1, tz));
}
}
// The example displays the following output on Windows XP systems:
// 3/21/2006 9:00:00 AM
// 3/21/2006 9:00:00 AM
// 3/21/2006 10:00:00 AM
open System
let date1 = DateTime(2006, 3, 21, 2, 0, 0)
printfn $"{date1.ToUniversalTime()}"
printfn $"{TimeZoneInfo.ConvertTimeToUtc date1}"
let tz = TimeZoneInfo.FindSystemTimeZoneById "Pacific Standard Time"
printfn $"{TimeZoneInfo.ConvertTimeToUtc(date1, tz)}"
// The example displays the following output on Windows XP systems:
// 3/21/2006 9:00:00 AM
// 3/21/2006 9:00:00 AM
// 3/21/2006 10:00:00 AM
Module Example
Public Sub Main()
Dim date1 As Date = #3/21/2006 2:00AM#
Console.WriteLine(date1.ToUniversalTime())
Console.WriteLine(TimeZoneInfo.ConvertTimeToUtc(date1))
Dim tz As TimeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time")
Console.WriteLine(TimeZoneInfo.ConvertTimeToUtc(date1, tz))
End Sub
End Module
' The example displays the following output on Windows XP systems:
' 3/21/2006 9:00:00 AM
' 3/21/2006 9:00:00 AM
' 3/21/2006 10:00:00 AM
Si applica a
Vedi anche
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