How to represent a DateTime in Excel

Question

What is the best way of representing a DateTime in Excel? We use Syncfusions Essential XlsIO to output values to an Excel document which works great. But I can\

Answer 1

Excel expects dates and times to be stored as a floating point number whose value depends on the Date1904 setting of the workbook, plus a number format such as "mm/dd/yyyy" or "hh:mm:ss" or "mm/dd/yyyy hh:mm:ss" so that the number is displayed to the user as a date / time.

Using SpreadsheetGear for .NET you can do this: worksheet.Cells["A1"].Value = DateTime.Now;

This will convert the DateTime to a double which is the underlying type which Excel uses for a Date / Time, and then format the cell with a default date and / or time number format automatically depending on the value.

SpreadsheetGear also has IWorkbook.DateTimeToNumber(DateTime) and NumberToDateTime(double) methods which convert from .NET DateTime objects to a double which Excel can use.

I would expect XlsIO to have something similar.

Disclaimer: I own SpreadsheetGear LLC