Elliot,
I imagine the code in the add-In is driven by a button or menu click, or
triggered by an Excel event.
If started any of these ways, your code has freedom to the whole Excel
interface.
Whilst there may be ways of exceeding the bounds of a UDF, I would question
your real need to do so, as you would be going against the design of Excel .

NickHK

"Elliot" wrote in message
...
Hi,

I know that from vba a udf (and any other code called by that udf) may not
alter the worksheet in any way.

However i have an addin from another product, and it has functions that do
more than just return a value to that cell. Does this require a call to a
dll ??

I tried implementing an asynchronous call (to ADO) and wired up an event
but
that just made excel crash.

Thanks Elliot