I've got a bit of an issue that I'm trying to work out.

I have the page structure described in the subject, and performance
seems to have taken a nose dive, from perfectly acceptable at 8
DataList rows to Hideously Bad at 150 (the difference between the dev/
test system and the production system).

I'm looking for ways to improve performance.  So far, I've made a big
difference by getting the ViewState and ControlState out of the page
and into the session, but I still need to do more.

Each row of the DataList has a set of bound controls, including a
DataGrid made hideable with a CollapsiblePanelExtender, the DataGrids
have 7 bound columns (1 checkbox, 5 text fields bound to literals, and
1 column with bound imagebuttons).

Currently, when the results aren't filtered (the default), the users
on production are seeing warnings about a slow script when the
UpdatePanel containing the DataList is updated.  I suspect it's the
client-side portion of the AJAX process, busy handling about 1MB of
data that's just come down the wire.

I really need help on this one.

- Theo