custom columns in display formats

Hi

How easy is it to generate custom columns in content lists?

We would like to add a column that show the number of active assembly relationship so that users don’t have to use impact analysis on the items where this is 0.

Is this possible? I know the columns are currently restricted to system, shared and local fields but there is a custom thumbnail preview so know that something may be possible.

Cheers
James

I think it would be possible, but would require unsupported changes. You would need to add a ‘read-only’ system field, whose datasource was an extension. The extension would perform the calculation and return the results. Such a change would survive upgrade.

The thumbnail preview requires a column to be present in the content type to which it adds the URL, thus it would not be very useful unless you wanted to add a column to all the content types for which you wanted to display the AA rel count.

One concern I would have about such an extension is performance.