DateTime.AddDays(Double) DateTime.AddDays(Double) DateTime.AddDays(Double) DateTime.AddDays(Double) Method

定義

このインスタンスの値に、指定された日数を加算した新しい DateTime を返します。Returns a new DateTime that adds the specified number of days to the value of this instance.

public:
 DateTime AddDays(double value);
public DateTime AddDays (double value);
member this.AddDays : double -> DateTime
Public Function AddDays (value As Double) As DateTime

パラメーター

value
Double Double Double Double

整数部と小数部から成る日数。A number of whole and fractional days. value パラメーターは、正または負のどちらの場合もあります。The value parameter can be negative or positive.

戻り値

このインスタンスで表された日付と時刻に value で表された日数を加算した値を保持するオブジェクト。An object whose value is the sum of the date and time represented by this instance and the number of days represented by value.

例外

結果として返された DateTimeMinValue より小さいか、MaxValue より大きいです。The resulting DateTime is less than MinValue or greater than MaxValue.

次の例ではAddDays 、メソッドを使用して、現在の日付から36日後の曜日を確認します。The following example uses the AddDays method to determine the day of the week 36 days after the current date.

using namespace System;

int main()
{
   // Calculate what day of the week is 36 days from this instant.
   DateTime today = System::DateTime::Now;
   DateTime answer = today.AddDays( 36 );
   Console::WriteLine("Today: {0:dddd}", today);
   Console::WriteLine("36 days from today: {0:dddd}", answer);
}
// The example displays output like the following:
//       Today: Wednesday
//       36 days from today: Thursday
using System;

class Class1
{
	static void Main()
	{
		DateTime today = DateTime.Now;
		DateTime answer = today.AddDays(36);
        Console.WriteLine("Today: {0:dddd}", today);
        Console.WriteLine("36 days from today: {0:dddd}", answer);
	}
}
// The example displays output like the following:
//       Today: Wednesday
//       36 days from today: Thursday
Class Class1
   Public Shared Sub Main()
      Dim today As System.DateTime
      Dim answer As System.DateTime

      today = System.DateTime.Now
      answer = today.AddDays(36)

      Console.WriteLine("Today: {0:dddd}", today)
      Console.WriteLine("36 days from today: {0:dddd}", answer)
   End Sub
End Class
' The example displays output like the following:
'       Today: Wednesday
'       36 days from today: Thursday

注釈

このメソッドは、このDateTimeの値を変更しません。This method does not change the value of this DateTime. 代わりに、この操作の結果DateTimeを値として持つ新しいを返します。Instead, it returns a new DateTime whose value is the result of this operation.

value小数部は、1日の小数部です。The fractional part of value is the fractional part of a day. たとえば、4.5 は、4日、12時間、0分、0秒、0ミリ秒、および0ティックに相当します。For example, 4.5 is equivalent to 4 days, 12 hours, 0 minutes, 0 seconds, 0 milliseconds, and 0 ticks.

valueパラメーターは、ミリ秒単位で丸められます。The value parameter is rounded to the nearest millisecond.

このAddDaysメソッドは、日付の算術演算を実行するときに、うるう年と、月の日数を考慮します。The AddDays method takes into account leap years and the number of days in a month when performing date arithmetic.

適用対象

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