C# Julian 日期解析器

发布于 2024-07-13 00:34:55 字数 195 浏览 8 评论 0原文

我在电子表格中有一个单元格，它是 Excel 中的日期对象，但当它来自 C1 的 xls 类时，它会变成双精度型（类似于 2009 年 1 月 7 日的 39820.0）。我读到这是儒略日期格式。有人能告诉我如何在 C# 中将其解析回 DateTime 吗？

更新：看起来我可能没有儒略日期，而是自 1899 年 12 月 30 日以来的天数。

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仅此而已 2024-07-20 00:34:55

我认为 Excel 只是使用标准的 OLE 自动化 DATE 类型，可以是使用 DateTime.FromOADate 方法进行转换。

该代码块

using System;

namespace DateFromDouble
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine(DateTime.FromOADate(39820.0));
        }
    }
}

输出：

1/7/2009 12:00:00 AM

I think Excel is just using the standard OLE Automation DATE type which can be converted with the DateTime.FromOADate method.

This block of code,

using System;

namespace DateFromDouble
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine(DateTime.FromOADate(39820.0));
        }
    }
}

outputs:

1/7/2009 12:00:00 AM

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泪是无色的血 2024-07-20 00:34:55

System.Globalization中有一个JulianCalendar类；以下是您如何使用它：

            JulianCalendar c = new JulianCalendar();
            DateTime time = c.ToDateTime(2009, 1, 7, 0, 0, 0, 0);
            Console.WriteLine(time.ToShortDateString());

编辑：

如果实际上是自“1900”以来的几天，您可以这样做：

public static DateTime DaysSince1900(int days)
{
    return new DateTime(1900, 1, 1).AddDays(days);
}



 DateTime time = DaysSince1900(39820);
 Console.WriteLine(time.ToShortDateString()); //will result in "1/9/2009"

There's a JulianCalendar class in System.Globalization; Here's how you would use it:

            JulianCalendar c = new JulianCalendar();
            DateTime time = c.ToDateTime(2009, 1, 7, 0, 0, 0, 0);
            Console.WriteLine(time.ToShortDateString());

EDIT:

If it is in fact days since "1900" here's how you can do it:

public static DateTime DaysSince1900(int days)
{
    return new DateTime(1900, 1, 1).AddDays(days);
}



 DateTime time = DaysSince1900(39820);
 Console.WriteLine(time.ToShortDateString()); //will result in "1/9/2009"

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树深时见影 2024-07-20 00:34:55

该数字看起来像是“自 1900 年以来的天数”值。

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め七分饶幸 2024-07-20 00:34:55

有两种方法可以执行此转换 --

OLE 自动化日期方法 --

double doubleDate = 43153.0; 
  日期时间正常日期 = DateTime.FromOADate(doubleDate); 
  /* {2/22/2018 12:00:00 上午} */

DateAdd()方法，使用该方法，可以指定要转换成的日期类型

double doubleDate = 43153.0; 
  DateTime NormalDate = new DateTime(1899, 12, 30, 0, 0, 0, DateTimeKind.Utc).AddDays(doubleDate); 
  /* {2/22/2018 12:00:00 上午} */

注意：这个日期常量 {12h December 31, 1899} 称为都柏林儒略日，记录在儒略日

There are two ways to do this CONVERSION --

OLE Automation Date method --

double doubleDate = 43153.0;
DateTime normalDate = DateTime.FromOADate(doubleDate);
/* {2/22/2018 12:00:00 AM} */

DateAdd() Method, using this method, you can specify the kind of date to convert to

double doubleDate = 43153.0;
DateTime normalDate = new DateTime(1899, 12, 30, 0, 0, 0, DateTimeKind.Utc).AddDays(doubleDate);
/* {2/22/2018 12:00:00 AM} */

Note: This date constant {12h December 31, 1899} is called the Dublin Julian Day documented in Julian Day

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微凉徒眸意 2024-07-20 00:34:55

处理 Excel 日期时，日期可能是日期的字符串表示形式，也可能是 OA 日期。这是我不久前编写的一个扩展方法，以帮助促进日期转换：

/// <summary>
/// Sometimes the date from Excel is a string, other times it is an OA Date:
/// Excel stores date values as a Double representing the number of days from January 1, 1900.
/// Need to use the FromOADate method which takes a Double and converts to a Date.
/// OA = OLE Automation compatible.
/// </summary>
/// <param name="date">a string to parse into a date</param>
/// <returns>a DateTime value; if the string could not be parsed, returns DateTime.MinValue</returns>
public static DateTime ParseExcelDate( this string date )
{
    DateTime dt;
    if( DateTime.TryParse( date, out dt ) )
    {
        return dt;
    }

    double oaDate;
    if( double.TryParse( date, out oaDate ) )
    {
        return DateTime.FromOADate( oaDate );
    }

    return DateTime.MinValue;
}

When dealing with Excel dates, the date may be the string representation of a date, or it may be an OA date. This is an extension method I wrote a while back to help facilitate the date conversion:

/// <summary>
/// Sometimes the date from Excel is a string, other times it is an OA Date:
/// Excel stores date values as a Double representing the number of days from January 1, 1900.
/// Need to use the FromOADate method which takes a Double and converts to a Date.
/// OA = OLE Automation compatible.
/// </summary>
/// <param name="date">a string to parse into a date</param>
/// <returns>a DateTime value; if the string could not be parsed, returns DateTime.MinValue</returns>
public static DateTime ParseExcelDate( this string date )
{
    DateTime dt;
    if( DateTime.TryParse( date, out dt ) )
    {
        return dt;
    }

    double oaDate;
    if( double.TryParse( date, out oaDate ) )
    {
        return DateTime.FromOADate( oaDate );
    }

    return DateTime.MinValue;
}

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