DateTime.Now 屬性

定義

取得 DateTime 物件,此物件會設定為這部電腦上目前的日期和時間,以本地時間表示。Gets a DateTime object that is set to the current date and time on this computer, expressed as the local time.

public:
 static property DateTime Now { DateTime get(); };
public static DateTime Now { get; }
member this.Now : DateTime
Public Shared ReadOnly Property Now As DateTime

屬性值

物件,其值為目前的本地日期和時間。An object whose value is the current local date and time.

範例

下列範例會使用 NowUtcNow 屬性,以取得目前的當地日期和時間,以及目前的國際標準(UTC)日期和時間。The following example uses the Now and UtcNow properties to retrieve the current local date and time and the current universal coordinated (UTC) date and time. 然後,它會使用多個文化特性的格式設定慣例來顯示字串,以及其 Kind 屬性的值。It then uses the formatting conventions of a number of cultures to display the strings, along with the values of the their Kind properties.

using namespace System;
using namespace System::Globalization;

void main()
{
   DateTime localDate = DateTime::Now;
   DateTime utcDate = DateTime::UtcNow;
   array<String^>^ cultureNames = { "en-US", "en-GB", "fr-FR",
                                    "de-DE", "ru-RU" } ;

   for each (String^ cultureName in cultureNames) {
      CultureInfo^ culture = gcnew CultureInfo(cultureName);
      Console::WriteLine("{0}:", culture->NativeName);
      Console::WriteLine("   Local date and time: {0}, {1:G}",
                         localDate.ToString(culture), localDate.Kind);
      Console::WriteLine("   UTC date and time: {0}, {1:G}\n",
                         utcDate.ToString(culture), utcDate.Kind);
   }
}
// The example displays the following output:
//       English (United States):
//          Local date and time: 6/19/2015 10:35:50 AM, Local
//          UTC date and time: 6/19/2015 5:35:50 PM, Utc
//
//       English (United Kingdom):
//          Local date and time: 19/06/2015 10:35:50, Local
//          UTC date and time: 19/06/2015 17:35:50, Utc
//
//       français (France):
//          Local date and time: 19/06/2015 10:35:50, Local
//          UTC date and time: 19/06/2015 17:35:50, Utc
//
//       Deutsch (Deutschland):
//          Local date and time: 19.06.2015 10:35:50, Local
//          UTC date and time: 19.06.2015 17:35:50, Utc
//
//       русский (Россия):
//          Local date and time: 19.06.2015 10:35:50, Local
//          UTC date and time: 19.06.2015 17:35:50, Utc
using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      DateTime localDate = DateTime.Now;
      DateTime utcDate = DateTime.UtcNow;
      String[] cultureNames = { "en-US", "en-GB", "fr-FR",
                                "de-DE", "ru-RU" } ;

      foreach (var cultureName in cultureNames) {
         var culture = new CultureInfo(cultureName);
         Console.WriteLine("{0}:", culture.NativeName);
         Console.WriteLine("   Local date and time: {0}, {1:G}",
                           localDate.ToString(culture), localDate.Kind);
         Console.WriteLine("   UTC date and time: {0}, {1:G}\n",
                           utcDate.ToString(culture), utcDate.Kind);
      }
   }
}
// The example displays the following output:
//       English (United States):
//          Local date and time: 6/19/2015 10:35:50 AM, Local
//          UTC date and time: 6/19/2015 5:35:50 PM, Utc
//
//       English (United Kingdom):
//          Local date and time: 19/06/2015 10:35:50, Local
//          UTC date and time: 19/06/2015 17:35:50, Utc
//
//       français (France):
//          Local date and time: 19/06/2015 10:35:50, Local
//          UTC date and time: 19/06/2015 17:35:50, Utc
//
//       Deutsch (Deutschland):
//          Local date and time: 19.06.2015 10:35:50, Local
//          UTC date and time: 19.06.2015 17:35:50, Utc
//
//       русский (Россия):
//          Local date and time: 19.06.2015 10:35:50, Local
//          UTC date and time: 19.06.2015 17:35:50, Utc
Imports System.Globalization

Module Example
   Public Sub Main()
      Dim localDate = DateTime.Now
      Dim utcDate = DateTime.UtcNow
      Dim cultureNames() As String = { "en-US", "en-GB", "fr-FR",
                                       "de-DE", "ru-RU" }

      For Each cultureName In cultureNames
         Dim culture As New CultureInfo(cultureName)
         Console.WriteLine("{0}:", culture.NativeName)
         Console.WriteLine("   Local date and time: {0}, {1:G}",
                           localDate.ToString(culture), localDate.Kind)
         Console.WriteLine("   UTC date and time: {0}, {1:G}",
                           utcDate.ToString(culture), utcDate.Kind)
         Console.WriteLine()
      Next
   End Sub
End Module
' The example displays the following output:
'       English (United States):
'          Local date and time: 6/19/2015 10:35:50 AM, Local
'          UTC date and time: 6/19/2015 5:35:50 PM, Utc
'
'       English (United Kingdom):
'          Local date and time: 19/06/2015 10:35:50, Local
'          UTC date and time: 19/06/2015 17:35:50, Utc
'
'       français (France):
'          Local date and time: 19/06/2015 10:35:50, Local
'          UTC date and time: 19/06/2015 17:35:50, Utc
'
'       Deutsch (Deutschland):
'          Local date and time: 19.06.2015 10:35:50, Local
'          UTC date and time: 19.06.2015 17:35:50, Utc
'
'       русский (Россия):
'          Local date and time: 19.06.2015 10:35:50, Local
'          UTC date and time: 19.06.2015 17:35:50, Utc

備註

Now 屬性會傳回 DateTime 值,表示本機電腦上的目前日期和時間。The Now property returns a DateTime value that represents the current date and time on the local computer. 請注意,DateTime 值之間有差異,這代表自0001年1月1日午夜起已經過的刻度數,以及該 DateTime 值的字串標記法,以特定文化特性(culture)特定格式來表示日期和時間值。Note that there is a difference between a DateTime value, which represents the number of ticks that have elapsed since midnight of January 1, 0001, and the string representation of that DateTime value, which expresses a date and time value in a culture-specific-specific format. 如需格式化日期和時間值的相關資訊,請參閱 ToString 方法。For information on formatting date and time values, see the ToString method. 下列範例會以一些特定文化特性格式來顯示簡短的日期和時間字串。The following example displays the short date and time string in a number of culture-specific formats.

using namespace System;
using namespace System::Globalization;

void main()
{
   DateTime localDate = DateTime::Now;
   array<String^>^ cultureNames = { "en-US", "en-GB", "fr-FR",
                                    "de-DE", "ru-RU" };

   for each (String^ cultureName in cultureNames) {
      CultureInfo^ culture = gcnew CultureInfo(cultureName);
      Console::WriteLine("{0}: {1}", cultureName,
                         localDate.ToString(culture));
   }
}
// The example displays the following output:
//       en-US: 6/19/2015 10:03:06 AM
//       en-GB: 19/06/2015 10:03:06
//       fr-FR: 19/06/2015 10:03:06
//       de-DE: 19.06.2015 10:03:06
//       ru-RU: 19.06.2015 10:03:06
using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      DateTime localDate = DateTime.Now;
      String[] cultureNames = { "en-US", "en-GB", "fr-FR",
                                "de-DE", "ru-RU" };

      foreach (var cultureName in cultureNames) {
         var culture = new CultureInfo(cultureName);
         Console.WriteLine("{0}: {1}", cultureName,
                           localDate.ToString(culture));
      }
   }
}
// The example displays the following output:
//       en-US: 6/19/2015 10:03:06 AM
//       en-GB: 19/06/2015 10:03:06
//       fr-FR: 19/06/2015 10:03:06
//       de-DE: 19.06.2015 10:03:06
//       ru-RU: 19.06.2015 10:03:06
Imports System.Globalization

Module Example
   Public Sub Main()
      Dim localDate = DateTime.Now
      Dim cultureNames() As String = { "en-US", "en-GB", "fr-FR",
                                       "de-DE", "ru-RU" }

      For Each cultureName In cultureNames
         Dim culture As New CultureInfo(cultureName)
         Console.WriteLine("{0}: {1}", cultureName,
                           localDate.ToString(culture))
      Next
   End Sub
End Module
' The example displays the following output:
'    en-US: 6/19/2015 10:03:06 AM
'    en-GB: 19/06/2015 10:03:06
'    fr-FR: 19/06/2015 10:03:06
'    de-DE: 19.06.2015 10:03:06
'    ru-RU: 19.06.2015 10:03:06

這個屬性的解決方式取決於系統計時器,這取決於基礎作業系統。The resolution of this property depends on the system timer, which depends on the underlying operating system. 通常是介於0.5 和15毫秒之間。It tends to be between 0.5 and 15 milliseconds. 因此,在短時間間隔內重複呼叫 Now 屬性(例如在迴圈中)可能會傳回相同的值。As a result, repeated calls to the Now property in a short time interval, such as in a loop, may return the same value.

Now 屬性經常用來測量效能。The Now property is frequently used to measure performance. 不過,因為它的低解析度,所以不適合用來做為基準工具。However, because of its low resolution, it is not suitable for use as a benchmarking tool. 更好的替代方式是使用 Stopwatch 類別。A better alternative is to use the Stopwatch class.

從 .NET Framework 版本2.0 開始,傳回值是 Kind 屬性傳回 DateTimeKind.LocalDateTimeStarting with the .NET Framework version 2.0, the return value is a DateTime whose Kind property returns DateTimeKind.Local.

注意

您也可以使用 DateTimeOffset.Now 屬性來取出目前的本機日期和時間。You can also use the DateTimeOffset.Now property to retrieve the current local date and time. 它允許以單一時間點明確表示當地時間,進而讓該時間值可在電腦間攜帶。It allows a local time to be expressed unambiguously as a single point in time, which in turn makes that time value portable across computers.

適用於

另請參閱