How to convert a double value to a DateTime in c#?

Question

I have the value 40880.051388 and am storing it as a double, if I open Excel and paste in a cell and apply the following custom format \"m/d/yyyy h:mm\" to that

Answer 1

The value is an offset in days from December 30th, 1899. So you want:

new DateTime(1899, 12, 30).AddDays(40880.051388)