batch update excel with add-in

Hello,

I want to automatically update an excel file in batch mode.

since my excel file have an add-in and lot of cells need to be updated
by the add-in functions.
I set auto calculation in workbook's open event and remove the fomular
after update is done.


The steps that I am doing now is

1. Open my excel file using C# DDE (interop)

2. Call a micro to remove the formula

3. Save my excel file

4. quit excel

And the problem is that if there are just about 10 Cells need to call
add-in function, the above steps work fine. However, when the number
of cells is big, for example 500, all the cells have '#Name?'.
it seems that there is no enought time to allow add-in function to
finish.

so what should I do?


Any Help. Thanks.