How to convert DateTime to Excel Date?

[Dorell]

Hi All

I’m trying to insert dates directly into an Excel file but Excel is not
recognising the values as dates. At the moment I’m calculating the total
number of days between “30/12/1899 00:00:00†and the specified dates using
the TimeSpan class but the result is never exactly the same as an Excel date,
there’s always a slight, slight difference at the end of the decimal value.

Is there a standard way in C# to convert a DateTime (“29/03/2009 20:53:26â€)
to an Excel date (39901.870439814818)?

Thanks
Jason

 

[Andrei Smolin [Add-in Express]]

Hi Jason,

See System.DateTime.ToOADate(). Note also, that you can then format the cell
in the way you like. See how we do the same thing in an XLL add-in published
at
http://www.add-in-express.com/docs/net-excel-udf-tips.php#returning-dates.

Regards from Belarus (GMT+2),

Andrei Smolin
Add-in Express Team Leader
www.add-in-express.com

 

[Dorell]

Great thanks Andrei

Hi Jason,

See System.DateTime.ToOADate(). Note also, that you can then format the cell
in the way you like. See how we do the same thing in an XLL add-in published
at
http://www.add-in-express.com/docs/net-excel-udf-tips.php#returning-dates.

Regards from Belarus (GMT+2),

Andrei Smolin
Add-in Express Team Leader
www.add-in-express.com