DateTime.Now プロパティ

定義

コンピューター上の現在の日時を現地時刻で表した DateTime オブジェクトを取得します。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

プロパティ値

現在の現地日時を値として保持するオブジェクト。An object whose value is the current local date and time.

次の例では、NowUtcNow のプロパティを使用して、現在の現地日時と現在の世界協定 (UTC) 日付と時刻を取得します。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. 次に、さまざまなカルチャの書式指定規則を使用して、Kind のプロパティの値と共に文字列を表示します。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

注釈

Now プロパティは、ローカルコンピューター上の現在の日付と時刻を表す DateTime 値を返します。The Now property returns a DateTime value that represents the current date and time on the local computer. DateTime 値には、0001年1月1日の午前0時から経過したタイマー刻みの数と、カルチャ固有の形式で日付と時刻の値を表す DateTime 値の文字列形式を表している点に注意してください。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. 日付と時刻の値の書式設定の詳細については、ToString メソッドを参照してください。For information on formatting date and time values, see the ToString method. 次の例では、短い日付と時刻の文字列を、カルチャ固有のさまざまな形式で表示します。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

このプロパティの解決策は、基になるオペレーティングシステムに依存するシステムタイマーによって異なります。The resolution of this property depends on the system timer, which depends on the underlying operating system. 0.5 ~ 15 ミリ秒の範囲で指定します。It tends to be between 0.5 and 15 milliseconds. その結果、ループ内などの短い時間間隔で Now プロパティを繰り返し呼び出すと、同じ値が返される可能性があります。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 プロパティは、パフォーマンスを測定するためによく使用されます。The Now property is frequently used to measure performance. ただし、解像度が低いため、ベンチマークツールとしての使用には適していません。However, because of its low resolution, it is not suitable for use as a benchmarking tool. 代わりに、Stopwatch クラスを使用することをお勧めします。A better alternative is to use the Stopwatch class.

.NET Framework バージョン2.0 以降、戻り値は Kind プロパティが DateTimeKind.Localを返す DateTime です。Starting with the .NET Framework version 2.0, the return value is a DateTime whose Kind property returns DateTimeKind.Local.

注意

また、DateTimeOffset.Now プロパティを使用して、現在のローカルの日付と時刻を取得することもできます。You can also use the DateTimeOffset.Now property to retrieve the current local date and time. ローカル時刻を1つの時点として明確に表現できるため、その時刻値はコンピューター間で移植可能になります。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.

適用対象

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