Nothing is built into Outlook like an autonumber field in Access. Whatever solution you decide to use will require code behind a custom form or add-in.
If a simple unique identifier will do, you can take the item's EntryID (set after the item is saved) and copy it into the field that you want to use to hold the ID. The value of the actual EntryID property may change if you move the item, but the value in the custom property won't.
My book demonstrates several other methods. You can download the sample code from
http://www.outlookcode.com/member/book.aspx :
1) Get a GUID with the Session.CreateConversationIndex from CDO 1.21. (Listing 20.5)
2) Build an ID from the current date/time (Listing 20.6)
If you need a sequential number, not just a unique number, here are some methods you can use:
3) Use an autonumber table in SQL Server or Microsoft Access. (In my book, Listing 23.7 with Listing 23.4 or 23.3 to open the database)
4) In a custom Outlook form, republish the form after each use to reset the number. See
http://www.outlookexchange.com/articles/ricardosilva/vbscriptoutforms.asp
5) Use an Excel worksheet that contains VBA code to increment the number. See
http://www.microsoft.com/office/com...sers&mid=5489e140-9794-41b7-a9ba-1324e136ff3a
--
Sue Mosher, Outlook MVP
Author of Configuring Microsoft Outlook 2003
and Microsoft Outlook Programming - Jumpstart for
Administrators, Power Users, and Developers