See

http://www.cpearson.com/Excel/CreatingCOMAddIn.aspx and
http://www.cpearson.com/Excel/COMAddIn2007.aspx and
http://www.cpearson.com/Excel/AutomationAddIns.aspx


--
Cordially,
Chip Pearson
Microsoft Most Valuable Professional
Excel Product Group
Pearson Software Consulting, LLC
www.cpearson.com
(email on web site)




"JAC" wrote in message
...
Extending Excel 2003 with VBA, I should like to separate most of the
code from the workbook (~90%+) and put it into a DLL (rather than an
Excel add-in .xla), which will act as a black box. I think this is
called a COM Add-in.

I do not necessarily require worksheet functions from the DLL, but
rather to place VBA code modules and classes there and call the code
from what is really a simple library.

This is a rather naive view.

Has anyone experience of this? Do I really require the
IDTExtensibility2 interface?

Any general advice would be most welcome.

Thank you in anticipation.