JapaneseCalendar.ToDateTime Method

public:
 override DateTime ToDateTime(int year, int month, int day, int hour, int minute, int second, int millisecond, int era);

public override DateTime ToDateTime (int year, int month, int day, int hour, int minute, int second, int millisecond, int era);

override this.ToDateTime : int * int * int * int * int * int * int * int -> DateTime

Public Overrides Function ToDateTime (year As Integer, month As Integer, day As Integer, hour As Integer, minute As Integer, second As Integer, millisecond As Integer, era As Integer) As DateTime

Parameters

Returns

The DateTime that is set to the specified date and time in the current era.

Exceptions

Examples

The following example instantiates two dates. The first is always the first day of the second year in the current era, while the second identifies a specific day in the Taisho era. The output from the example was produced with the Heisei era as the current era.

using System;
using System.Globalization;

class Program
{
    static void Main()
    {
        var cal = new JapaneseCalendar();
        var jaJp = new CultureInfo("ja-JP");
        jaJp.DateTimeFormat.Calendar = cal;
        var date1 = cal.ToDateTime(2,1,1,0,0,0,0,JapaneseCalendar.CurrentEra);
        Console.WriteLine($"Japanese calendar date: {date1.ToString("D", jaJp)}, " +
                          $"Gregorian calendar date: {date1.ToString("D", CultureInfo.InvariantCulture)}");

        var date2 = cal.ToDateTime(6,11,7,0,0,0,0,GetEraIndex("大正"));
        Console.WriteLine($"Japanese calendar date: {date2.ToString("D", jaJp)}, " +
                          $"Gregorian calendar date: {date2.ToString("D", CultureInfo.InvariantCulture)}");

        int GetEraIndex(string eraName)
        {
           foreach (var ctr in cal.Eras)
              if (jaJp.DateTimeFormat.GetEraName(ctr) == eraName)
                 return ctr;

           return 0; 
        }
    }
}
// The example displays the following output:
//   Japanese calendar date: 平成2年1月1日, Gregorian calendar date: Monday, 01 January 1990
//   Japanese calendar date: 大正6年11月7日, Gregorian calendar date: Wednesday, 07 November 1917

Imports System.Globalization

Module Program
    Dim cal As Calendar
    Dim jaJp As CultureInfo
    
    Public Sub Main()
        cal = New JapaneseCalendar()
        jaJp = New CultureInfo("ja-JP")
        jaJp.DateTimeFormat.Calendar = cal
        Dim date1 = cal.ToDateTime(2,1,1,0,0,0,0,JapaneseCalendar.CurrentEra)
        Console.WriteLine($"Japanese calendar date: {date1.ToString("D", jaJp)}, " +
                          $"Gregorian calendar date: {date1.ToString("D", CultureInfo.InvariantCulture)}")

        Dim date2 = cal.ToDateTime(6,11,7,0,0,0,0,GetEraIndex("大正"))
        Console.WriteLine($"Japanese calendar date: {date2.ToString("D", jaJp)}, " +
                          $"Gregorian calendar date: {date2.ToString("D", CultureInfo.InvariantCulture)}")
    End Sub

    Private Function GetEraIndex(eraName As String) As Integer
        For Each ctr in cal.Eras
            If jaJp.DateTimeFormat.GetEraName(ctr) = eraName Then Return ctr
        Next

        Return 0 
    End Function
End Module
' The example displays the following output:
'   Japanese calendar date: 平成2年1月1日, Gregorian calendar date: Monday, 01 January 1990
'   Japanese calendar date: 大正6年11月7日, Gregorian calendar date: Wednesday, 07 November 1917

Remarks

The ToDateTime method is useful because it can convert any date in the current calendar to a Gregorian calendar date. The Gregorian date can subsequently be used, for example, to compare dates in different calendars or create an equivalent date in a particular calendar.

Because the JapaneseCalendar supports multiple eras based on the reign of the emperor, you should always call this method and explicitly specify an era to avoid an unintended date and to make the intent of your code clear. The example shows how to instantiate a date that is always in the current era and one that belongs to a specified era.

Applies to

See also

• DateTime
• CurrentEra
• Eras
• GetMonthsInYear(Int32, Int32)
• GetDaysInMonth(Int32, Int32, Int32)