Question

I have a set of calculation methods sitting in a .Net DLL. I would like to make those methods available to Excel (2003+) users so they can use them in their spreadsheets.

For example, my .net method:

public double CalculateSomethingReallyComplex(double a, double b) {...} 

I would like enable them to call this method just by typing a formula in a random cell:

=CalculateSomethingReallyComplex(A1, B1) 

What would be the best way to accomplish this?

Answer 1

There are two methods – you can used Visual Studio Tools for Office (VSTO):

http://blogs.msdn.com/pstubbs/archive/2004/12/31/344964.aspx

or you can use COM:

http://blogs.msdn.com/eric_carter/archive/2004/12/01/273127.aspx

I’m not sure if the VSTO method would work in older versions of Excel, but the COM method should work fine.