[bugs #4690] NSBrowser loads all cells for passive delegate

[Alexander Malmberg]

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/**************************************************************************/
[bugs #4690] Latest Modifications:

Changes by: 
                Alexander Malmberg <alexander@malmberg.org>
'Date: 
                Sat 09/25/04 at 22:42 (Europe/Stockholm)

            What     | Removed                   | Added
---------------------------------------------------------------------------
          Item Group | Bug                       | Change Request


------------------ Additional Follow-up Comments ----------------------------
The difference between an active and a passive delegate lies in the messages 
they use to fill the browser with data. Thus, there's no guarantee that cells 
will be loaded on demand for a passive delegate, so this isn't a bug.

While it would be nice to be able to do this, it isn't easy to implement, and I 
don't see any way of doing it that doesn't involve slightly changing the 
interface towards custom matrix/cell classes. The most tempting alternative 
would be to extend NSMatrix to let you create cells on demand and then use this 
from NSBrowser (this is also the only alternative that avoids creating tons of 
browser cells up-front).

Anyway, in the absence of something that depends critically on this, or (really 
good) patches that implement it, I don't think I'll look more at it; not enough 
benefit for the complexity and effort.

I don't really know what we want our policy to be for things like this; for 
now, I'll leave it open as a "Change request".






/**************************************************************************/
[bugs #4690] Full Item Snapshot:

URL: <http://savannah.gnu.org/bugs/?func=detailitem&item_id=4690>
Project: GNUstep
Submitted by: Stefan Urbanek
On: Sat 08/09/03 at 15:13

Category:  Gui/AppKit
Severity:  3 - Ordinary
Item Group:  Change Request
Resolution:  None
Privacy:  Public
Assigned to:  None
Status:  Open


Summary:  NSBrowser loads all cells for passive delegate

Original Submission:  When using NSBrowser and a passive delegate 
(numberOfRows... and willDisplayCell:...), the browser loads all cells. This 
makes no difference between the passive and the active delegate.

In my application i have a column with 1000+ items (cells), and they are all 
loaded instead of just a few (say 5-10) that are going to be displayed.

I have tested this with rIO's HelpViewer and got the same result.


Follow-up Comments
------------------


-------------------------------------------------------
Date: Sat 09/25/04 at 22:42         By: Alexander Malmberg <alexm>
The difference between an active and a passive delegate lies in the messages 
they use to fill the browser with data. Thus, there's no guarantee that cells 
will be loaded on demand for a passive delegate, so this isn't a bug.

While it would be nice to be able to do this, it isn't easy to implement, and I 
don't see any way of doing it that doesn't involve slightly changing the 
interface towards custom matrix/cell classes. The most tempting alternative 
would be to extend NSMatrix to let you create cells on demand and then use this 
from NSBrowser (this is also the only alternative that avoids creating tons of 
browser cells up-front).

Anyway, in the absence of something that depends critically on this, or (really 
good) patches that implement it, I don't think I'll look more at it; not enough 
benefit for the complexity and effort.

I don't really know what we want our policy to be for things like this; for 
now, I'll leave it open as a "Change request".












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