Virtual paging and groups

[wavetrexParticipant]

Hello !

I have built a grid which uses virtual paging and also groups information on certain columns.

I have a problem with groups which only occurs when using the virtual paging ( when letting the grid do the paging on all loaded data it doesn’t occur ):
When the number of rows returned by the server is smaller than the page size, the grid attempts to show and group by some rows that do not exist:

http://imageshack.us/photo/my-images/541/bug1q.jpg/

If I remove the grouping, it only shows ( and allows me to select ) the actual existing rows:

http://imageshack.us/photo/my-images/13/bug2dg.jpg/

Also, if Virtual Paging is disabled, it works fine with groups as well:

http://imageshack.us/photo/my-images/600/bug3d.jpg/

—
Code when virtual paging is enabled:

…
virtualmode: true, // virtual paging
rendergridrows: function(params)
{
return params.data;
},
groupable: true,
…

Any clue why this could be happening and how to fix it ?
Thanks !

[wavetrexParticipant]

Extra information:
– jqx version 2.8 (last)
– jquery 1.8.3
– browser: Any (it isn’t a display problem)

[Peter StoevKeymaster]

Hi wavetrex,

We will investigate the reported behavior. In case we reproduce it, we will create a work item about it and schedule a fix for a future version.

Best Regards,
Peter Stoev

jQWidgets Team
http://www.jqwidgets.com

[gediminasMember]

Hello,

I am having the same issue and would love to hear about the possible solutions.
Thanks in advance!

[Peter StoevKeymaster]

Hi gediminas,

We cannot offer a solution for virtual paging with grouping. In virtual mode the data is loaded on demand and is not stored in the Grid. The grouping works with data that is already loaded in the Grid.

Best Regards,
Peter Stoev

jQWidgets Team
http://www.jqwidgets.com

[wavetrexParticipant]

To me it looks like it calculates the groups from the rows on the current page.
That’s totally Ok, I don’t need it to group something “not already loaded in the Grid”

What I don’t understand is why it creates/shows fake rows, which can be selected but obviously contain only nulls … as it attempts to “fill” the grid up to the page size.

—
I tried setting the page size to the number of actual loaded rows, which appears to “fix” the problem, but also forces the data on that page to be loaded again (when using virtual mode).

The real solution would obviously be in the group assembly code… so if only 17 rows are currently on the screen… well, it should group those 17 only, ignoring the page size ! It’s clear that the grid knows what are the elements currently visible, without any active groups it displays just those rows perfectly !

Perhaps you can find a way… Maybe it is as simple as choosing the number of currently loaded rows instead of the number of items on a page. (Switch one variable for the other)

Thanks,
Wave.

[wavetrexParticipant]

Hello, any update on this matter ?

Over two months since…
I tried everything possible to make the fake group with fake rows disappear, without luck

http://img22.imageshack.us/img22/6366/gridbug.png

Please tell me you are at least considering fixing this !
It makes using groups very distracting for users … and while it is a great feature, not really usable with this problem.

Thank you !

[wavetrexParticipant]

Sorry for posting multiple times, but I’ve had bad experience with trying to edit my post (accidentally moved it into another thread) !

So… something which might help debugging:

In the example corresponding to the posted picture:
“getrows” and “getboundrows” methods return an array of 3 items ( which contain the actual data )

however,
“getdisplayrows” contains … well, 18 items, 3 “group rows” and 15 “data rows”, from which obviously only the first three are correct.

I even attempted to use “deleterow” with a rowid > 3, nothing happens, which is logical, since there are really only 3 rows in the bound data !

My guess is that somewhere in the code where grouping happens there is a missing condition when looping from 0 to PageSize to check if the bound row index actually exists:

Using “getgroup” method on the third (fake) group, returns this:

expanded: true
group: “”
level: 0
subgroups: []
subrows: [undefined, undefined, undefined, 9 more…]
0: undefined
1: undefined
2: undefined
3: undefined
4: undefined
5: undefined
… and so on.

Please, pretty please with sugar on top, try to fix this before 1st of July this year, we’re trying to launch the application as version 1.0 RC at that time, which means finally some income, which means jqWidgets licenses … for both the people which will use the system comercially, and also for myself a developer license, …. that means everyone’s happy ! But with this really visible problem it will be very difficult to convince the customers that it’s “working as intended”.

Thank you again !
Alin

[Author]

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