ToOADate(); Convert Julian Date Excel

Question

I am using OpenXML to read and excel spreadsheet and dates are stored as numbers. As I understand this is a julian format and every where I google says to use ToOADate(); to convert these numbers to dates.

The problem i am having is ToOADate(); does not resolve in my compile. I am using Visual Basic 2013, C# Asp.net MVC application.

It appears this is in the System Namespace, but I already have a using System statement.

I am obviously missing something very basic - can someone assist?

 var test = 41725;
DateTime test2 = test.ToOADate();

The compile error I am getting is

Error 4 'int' does not contain a definition for 'ToOADate' and no extension method 'ToOADate' accepting a first argument of type 'int' could be found (are you missing a using directive or an assembly reference?)

Answer 1

If you are converting numbers to Framework DateTime instances, it is likely you are after the static method on the DateTime struct.

        DateTime dt = DateTime.FromOADate(23456);

This method needs to be scoped to DateTime. In my example, the result is 20 March 1963.

There is also an instance method on DateTime which does the reverse...

        double d = dt.ToOADate();

The result in this case is 23456.

Your code indicates that you are trying to call it as an instance method on a int, and this will not work. The compiler is telling you that there is no such method on the int primitive.

Try instead...

 var test = 41725;
DateTime test2 = DateTime.FromOADate(test);

And you'll get 27 March 2014.