Creating a custom column: "Append-Only" File Upload

Question

I'm trying to make a custom column (for a custom list), where the users can upload files without overwriting the previous - this way they can keep past versions of the files and upload newer ones and the new ones append. There already exist "append only" comment columns and file upload columns that I can see.

I'm working with Sharepoint designer 2007 (2010 doesn't work with the site), and I'm referencing this code I found online somewhere (http://pastebin.com/raw.php?i=0qN89meu), trying to research the Sharepoint documentation on MSDN. I can open the site in designer, but don't know where to go from there (it's already running on a web server, not opening it locally).

I'm just not clear on how to start, I thought there'd be a simple "right+click -> new column" feature but I can't find it. If someone could point me in the right direction to where I could start creating columns on the site, that would be great. Thanks!

Answer 1

An untested idea :

1. Create a document library with a lookup column to the custom list.
2. Create an event receiver (ItemAdded and ItemUpdated) than will take the attached files and move them to the other list (with the correct lookup value). --> Code with Visual Studio
3. Grant to this document library only read permissions.
4. Adapt the view to display the related documents in the dispform of the custom list.

Advantages:

• this seems to answer to your need
• you gain all the usability of a document library (nothing prevent you to grant edit rights to other users, force check out, etc.)

Disadvantages:

• you have to play with lookup. Can be tricky sometimes, if you play with features
• you split one business entity to two entities. You will have to deal with cascading delete (if you need it).