Deferred scrollmode with virtualmode

[mkrajewParticipant]

I have a working grid that uses virtual scrolling and it loads as users scroll up and down the page. Since we are moving from client software to web-based, users are not used to having data download every time they scroll down, and that really slows down their work.

My plan was to download a json “index” of rows ahead of time and then enable deferred mode so as they scroll down I could look up where they are in the index based on row number and provide them hints with how far down the list they are. Then when they release, the data would load.

Of course now I’m finding that the deferred scrolling event does not work at all with virtual mode. I would request that you please add it. I know that the row data passed in would be minimal because the data is not yet loaded, but I would be happy with just a row number.

Also, limitations like these should really be put in the documentation. It is very frustrating trying things out, trying to figure out why they aren’t working, and then discovering through forum threads that they aren’t supported.

[HristoParticipant]

Hello mkrajew,

I tested this demo with Virtual Scrolling and it seems to work fine.

Yes, we do not support virtual mode with deferred scrolling.
About the combination of virtual mode with deferred scrolling should be thought which data to show on a particular position.
I will discuss this with my colleagues.

Best Regards,
Hristo Hristov

jQWidgets team
http://www.jqwidgets.com

[mkrajewParticipant]

Thanks for your consideration! I would be happy if the scrollfeedback event fired with just the row index the scrollbar is at if a row does not yet exist. That way I can maintain my own index of data outside the grid and display it in the deferred popup based on the index.

Alternatively, an alternate scrollfeedback_virtual event could be created if the row doesn’t exist, that provides just the row’s index. That way your currently scrollfeedback event would work exactly the same and all you’d be doing is adding another event.

[revenParticipant]

any update on this? I’m after the same thing.

I’m working on an inifinte scroll, which I have working. In the rendergridrows event, if the endindex is greater than the total data length I have – 100, then I grab more data from the server.

I havent found a scroll event, and this is the only way I’ve discovered to hook this up.

At this point, I could use deferred scrolling, as the user can only scroll to known data, when they reach the end (or near it), I block the UI and get more data. at no point can the scroll past the known dataset.

[HristoParticipant]

Hello reven,

We have come to an end and achieved a common understanding.
Please, read the suggestion above.
Also, we have a similar topic in the mentioned case.
Please, take a look at this topic.
You could change the source.totalrecords and on that way to enlarge the grid size.

Best Regards,
Hristo Hristov

jQWidgets team
https://www.jqwidgets.com

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