Scrolling issues when both virtual scrolling and paging are enabled

8 posts, 0 answers
  1. Nicholas
    Nicholas avatar
    27 posts
    Member since:
    Mar 2013

    Posted 09 Jan 2014 Link to this post

    Hi,

    Is having both virtual scrolling and traditional paging enabled a supported scenario? I have created a quick jsFiddle showing a bug with the pager control in this case:

    http://jsfiddle.net/xd2nb/1/

    To reproduce it, scroll a few pages down with the mouse wheel, then scroll up. The pager will "jump" between pages suddenly and/or briefly show the incorrect page number before eventually correcting itself after scrolling further.

    Is there a problem with my grid's configuration, or can this be addressed in a future update?

    Thanks,
    Nick
  2. Dimo
    Admin
    Dimo avatar
    8457 posts

    Posted 09 Jan 2014 Link to this post

    Hi Nick,

    The idea of virtual scrolling is to be used without paging. Using both features at the same time is unfortunately not supported.

    Regards,
    Dimo
    Telerik
    Join us on our journey to create the world's most complete HTML 5 UI Framework - download Kendo UI now!
  3. Nicholas
    Nicholas avatar
    27 posts
    Member since:
    Mar 2013

    Posted 09 Jan 2014 Link to this post

    Thanks.

    Is there really no way to get this working? I haven't dug into the grid's source code to find the problem myself, but it seems that since it already almost works, surely it must not be much of an effort to fix the page number being off occasionally?

    Unfortunately, my company has already drawn up UI outlines for our new application with the assumption that this would work, since we'd had both enabled and did not notice the problem until it was too late. If this scenario isn't supported, it would have been nice to have the grid throw an exception when enabling both and/or a note about it in the documentation.
  4. Dimo
    Admin
    Dimo avatar
    8457 posts

    Posted 09 Jan 2014 Link to this post

    Hi Nick,

    I am afraid that we have no plans to provide integration for paging and virtual scrolling and this is not as trivial as it looks.

    Frankly speaking, I do not see much benefit in having "partial virtualization" on per page basis. In case you can't pick one of the two featues as being more important than the other, then I would recommend you to use only paging.

    Regards,
    Dimo
    Telerik
    Join us on our journey to create the world's most complete HTML 5 UI Framework - download Kendo UI now!
  5. SwanB
    SwanB avatar
    50 posts
    Member since:
    Oct 2006

    Posted 11 Dec 2015 in reply to Dimo Link to this post

    Hi Dimo,

     

    thank you for your input regarding "not seeing much benefit in having partial virtualization on per page basis".

    As the partial virtualization according to you is not beneficial, I would appreciate very much if you please can advise us how to quickly and user friendly navigate to the mid or end of large datasets in the grid on a device using Virtual Scroll (with no scrollbar available). (Paging without Virtual Scroll is sooo much slower).

     

    Swan B

  6. Dimo
    Admin
    Dimo avatar
    8457 posts

    Posted 15 Dec 2015 Link to this post

    Hello Swan,

    No visible scrollbar implies a touch device. We recommend using paging instead of virtual scrolling on touch devices for faster navigation across a large data set.

    http://docs.telerik.com/kendo-ui/web/grid/appearance#virtual-scrolling

    When using mobile touch devices, which do not have a visible scrollbar that can be grabbed and dragged, virtual scrolling combined with a large number of data items, e.g. thousands, can impose a challenge to easily acccess all table rows, as this will require a great deal of touch scrolling.

    A possible way to facilitate access to the middle of the data set is to use some custom buttons that execute the page() method of the Grid dataSource.

    http://docs.telerik.com/kendo-ui/api/javascript/ui/grid#fields-dataSource

    http://docs.telerik.com/kendo-ui/api/javascript/data/datasource#methods-page

    Regards,
    Dimo
    Telerik
    Join us on our journey to create the world's most complete HTML 5 UI Framework - download Kendo UI now!
  7. SwanB
    SwanB avatar
    50 posts
    Member since:
    Oct 2006

    Posted 03 Oct 2017 in reply to Dimo Link to this post

    Any progress here,

    is the integration of paging and virtual scrolling still not as trivial as it looks.?

     

    Regards,

    SwanB

  8. Dimo
    Admin
    Dimo avatar
    8457 posts

    Posted 04 Oct 2017 Link to this post

    Hello SwanB,

    I confirm the state of affairs remains the same. Although we acknowledge the desire of customers to support this, there is no reliable way to scroll a virtual Grid to a particular table row, which is a prerequisite for the paging in this scenario to work as expected. I am sorry if this has negative implications for your business.

    http://docs.telerik.com/kendo-ui/controls/data-management/grid/appearance#limitations-for-virtual-scrolling

    Regards,
    Dimo
    Progress Telerik
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