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 t figure out how to display a DateTime in a column  Not when doing it myself directly in Excel either  Is it impossible  Do I have to use a separate date and a time column  I really wish I didn t  cause it kind of breaks sorting etc    unless Excel have something clever going on to fix that

User · Answer

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

User · Answer

Excel can display a Date type in a similar manner to a DateTime   Right click on the affected cell  select Format Cells  then under Category select Date and under Type select the type that looks something like this   3 14 01 1 30 PM   That should do what you requested   I tested sorting on some sample data with this format and it seemed to work fine

User · Answer

You can set date time values to a cell in XlsIO using one of these options  sheet Range  A1   Value2   DateTime Now  sheet Range  A1   NumberFormat    dd mm yyyy    sheet Range  A2   DateTime   DateTime Now  sheet Range  A2   NumberFormat      -409 d-mmm-yy       You can find more information here

User · Answer

Some versions of Excel don t have date-time formats available in the standard pick lists  but you can just enter a custom format string such as yyyy-mm-dd hh mm ss by    Right click -  Format Cells Number tab Choose Category Custom Enter your custom format string into the  Type  field   This works on my Excel 2010

User · Answer

If  like me  you can t find a datetime under date or time in the format dialog  you should be able to find it in  Custom    I just selected  dd mm yyyy hh mm  from  Custom  and am happy with the results

User · Answer

You can do the following     Datevalue text  timevalue text      Go into different types of date formats and choose    dd-mm-yyyy mm ss am pm

User · Answer

The underlying data type of a datetime in Excel is a 64-bit floating point number where the length of a day equals 1 and 1st Jan 1900 00 00 equals 1   So 11th June 2009 17 30 is about 39975 72917  If a cell contains a numeric value such as this  it can be converted to a datetime simply by applying a datetime format to the cell  So  if you can convert your datetimes to numbers using the above formula  output them to the relevant cells and then set the cell formats to the appropriate datetime format  e g  yyyy-mm-dd hh mm ss  then it should be possible to achieve what you want  Also Stefan de Bruijn has pointed out that there is a bug in Excel in that it incorrectly assumes 1900 is a leap year so you need to take that into account when making your calculations  Wikipedia

User · Answer

dd-mm-yyyy hh mm ss 000 Universal sortable date time pattern

[excel] How to represent a DateTime in Excel

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