On Sep 23, 2009, at 8:29 AM, David Bovill wrote:
I guess this is a question for you Trevor :)
In trying to debug an interface that makes asynchronous calls to
update a
datagrid I tacked donw the following feature / aspect of using:
set the dgDataOfIndex [indexNum] of grp "Datagrid" to recordArray
And that is that it calls you user defined "FillinData" twice, while:
set the dgData of grp "Datagrid" to dgArray
call "FillinData" only once.
When you update the data for a row in a Data Grid with rows of varying
height the data grid needs to recalculate the height of the row based
on the new data. This needs to happen regardless of whether or not the
control is visible on the screen as the total height of the Data Grid
content needs to be updated.
If the row you are updating is already being displayed in the Data
Grid then the visible control is redrawn. If the row isn't being
displayed in a control then a copy of your row template is created
just for this purpose (and then immediately destroyed). This is what
is going on in _UpdateIndexWithNewData.
The additional FillInData handler is probably being called from
_RedrawList beause _RefreshIndexes marks the row as dirty (this
happens in _ResetControlsOfIndex). In your particular circumstance I'm
not sure the row needs to be marked as dirty since it was updated in
_UpdateIndexWithNewData. I would have to look into this more closely
before I made any changes however.
Tracking this down using the executioncontexts it seems that "set the
dgDataOfIndex" first calls the handlers that "set the dgData" does
and then
in addition an extra:
I believe the calling chain in your cause would be as follows:
set the dgDataOfIndex
:_RefreshIndexes
:_UpdateIndexWithNewData (calls FillInData)
:_ResetControlsOfIndex
:_RedrawList (calls FillInData since the row was marked as
dirty)
In my case where I have a lot of action updating individual lines of
the
datagrid each second, I want to do this as fast as possible and also
to
avoid possible recursion with the async loads. It would help greatly
to
understand why "FillInData" needs to be called twice with "set the
dgDataOfIndex" and therefore what my handler should do with each call.
I will look into seeing if the 2nd call to FillInData can be removed
though it will have to wait until after the Pro App Dev course next
week.
--
Trevor DeVore
Blue Mango Learning Systems
ScreenSteps: http://www.screensteps.com
Application Development with Revolution Course:
http://revolution.bluemangolearning.com/software/revproappdev/
_______________________________________________
use-revolution mailing list
[email protected]
Please visit this url to subscribe, unsubscribe and manage your subscription
preferences:
http://lists.runrev.com/mailman/listinfo/use-revolution
