c# - 将 double 转换为日期时间？

Question

我有一个 .CSV 文件，我正在将其读入 C# 程序。在其中一列中，有一个日期，但它是“通用”格式，因此它在 .CSV 中显示为数字。例如:41172。

如何在 C# 中将此数字转换为格式为 dd/mm/yyyy 的日期？ 41172 相当于 2012 年 9 月 20 日。

Answer 1

要从“Excel 格式”的日期时间转换为 C# 日期时间，您可以使用 DateTime.FromOADate功能。

在你上面的例子中:

   DateTime myDate = DateTime.FromOADate(41172);

要以所需格式写出显示，请使用:

   myDate.ToString("dd/MM/yyyy");

如果您想知道 Excel 日期处理中的差异从何而来，那应该是故意的:

When Lotus 1-2-3 was first released, the program assumed that the year 1900 was a leap year even though it actually was not a leap year. This made it easier for the program to handle leap years and caused no harm to almost all date calculations in Lotus 1-2-3.

When Microsoft Multiplan and Microsoft Excel were released, they also assumed that 1900 was a leap year. This allowed Microsoft Multiplan and Microsoft Excel to use the same serial date system used by Lotus 1-2-3 and provide greater compatibility with Lotus 1-2-3. Treating 1900 as a leap year also made it easier for users to move worksheets from one program to the other.

Although it is technically possible to correct this behavior so that current versions of Microsoft Excel do not assume that 1900 is a leap year, the disadvantages of doing so outweigh the advantages.

来源:http://www.ozgrid.com/Excel/ExcelDateandTimes.htm