Create a VB.NET Class Library and write your functions in that library. This
is straight NET, no VSTO required.
http://www.cpearson.com/Excel/Creati...nctionLib.aspx

Personally, I think NET will be MUCH more tightly integrated with Office
(not via VSTO/SE, which strikes me as something of a hack job to get
*something* NET-related into Office) long before we see the demise of VBA.
(Remember, XLM is/was supported 12 years after is was made "obsolete" by
VBA.) There are millions upon millions of lines of VBA out in the world. I
doubt MS would abandon all of that code. VB6 is still fully supported (as in
it works, not as in MS provides tech support or updates) 6 years after is
was made obsolete by NET.

It is just my opinion, but NET has a long way to go to make it easily
integrated with Office.

--
Cordially,
Chip Pearson
Microsoft MVP - Excel, 10 Years
Pearson Software Consulting
www.cpearson.com
(email on the web site)


"Don" wrote in message
...
I read somewhere that Microsoft plans to drop support for VBA/VBE in office
apps in future releases of office for 64 bit OS. Remembering how fast the
uptake of 16 to 32 bit systems was, I figure it won't be long that most
office workstations will be 64 bit OS, so I decided to learn about VSTO.

One of the first things I learned was that you can't create UDFs in VSTO -
you have to use VBA (while VBA can interact with VSTO objects, you still
need
VBA).

So, the missing piece of info I have not been able to track down is how we
will be able to create UDF's in excel for environments where VBA is no
longer
supported. Perhaps I have misundestood something I read?