Hi,
It seem to me that what Larry has done (see earlier emails "Virtual fields for
a ds") works and stays within the philosophy of Dabo. As I see it, Larry
used the UI to change the presentation of the data to the user. That's what
the UI is for. The fake/virtual field is only created for the purposes of
displaying fake data (fake in the sense it is not persistent data) within a
Dabo grid that REQUIRES fields.
Larry's solution provides several benefits to the performance of the form.
For example changing from lbs to kilos requires no interaction with the back
end (Postgres in this case) and changes appear in an instant. The code is
self contained. As reported in the past, Larry's form is not as responsive
as it should be – so any performance increase is welcomed. For example
clicking on a check box within a Dabo grid does not respond instantly but
takes a least a half a second to display (on Linux).
However, there are a couple of issues that were raised immediately in my mind.
When I was helping Larry I kept asking “why were we subclassing
dGridDataTable” it just sounded wrong. Why not just use the SQL interface -
I asked. The second was dGridDataTable did not know about “self.Form”
another clue something might be wrong. But as I said in a earlier email
that I could not find a simple solution to the problem and Larry's solution
was providing immediate benefits.
So after some thought I've come to the conclusion there needs to be some sort
of Dabo interface that allows interaction with the grid fields beyond what is
currently available. I could have missed something within Dabo that solves
the issue. So if others have a better solution I (and I'm sure Larry too)
would like hear it.
I envision something like “thisform.function()” as a cell definition would be
nice. Ed has taken the first step with dabo.ui.dGrid.getTableClass(). Which
allows easy access – but I'd like to see more. I don't know what is required
to get my request done and I don't suggest I know how to write a Framework
interface. I'll leave that up to the experts like Ed and Paul. But I think
adding some means to directly use a function as a cell definition would
enhance Dabo.
--
John Fabiani
©2007 johnf |
