Windows Service and Excel AddIns


New member
Jul 6, 2004
Programming Experience

I wrote a Windows Service which will listen to incoming Emails.
Once it finds a valid attachment on a mail (*.xls), the File will be saved to a designated location and a macro in a *.xla file should be invoked opening the File and do some Accounting calculations on it.

The problem I have is, that when I write the code which checks xcel for all AddIns (*.xla files) I get a AddIn Count of 8 (in my case that is fine as there are 7 system AddIns and 1 custom AddIn which is the Accounting one).

BUT as I wrote a windows Service I have the problem, that within the Windows Service the count returned is always 7 (missing the custom *.xla).

Why does a Windows Form get 8 but the Windows Service only gets all AddIns which are not custom AddIns ?

I know that a windows Service does not show message boxes and so on... but all I have to do is kick of the macro which is in the AddIn file, therefore I don't understand how a windows service picks up all system (Excel default)AddIns but not the custom ones.

Is there a certain way a AddIn has to be installed so the windows Service can avail of it ?

Any help is appreaciated.