Intercepting scroll thumb drag events

8 posts, 0 answers
  1. scottw
    scottw avatar
    21 posts
    Member since:
    Oct 2010

    Posted 31 Jan 2011 Link to this post

    I am capturing scroll events (via gvLibrary.TableElement.VScrollBar.Scroll += this.gvLibrary_Scroll;) so that I can call a method on a lazy-loader class to update records in my buffer.  It's designed so that the 100,000+ records won't have to load all at once, but instead we load just a few pages of data at a time.  Each time the scroll is CLICKED, I am successfully able to trap the event and update my lazy-loaded queue.  However, if I drag the scroll bar, the event does not appear to fire.  Is there another event that I can use to handle when the scroll thumb is dragged?

    Thank you,

    VSmirk
  2. Richard Slade
    Richard Slade avatar
    3000 posts
    Member since:
    May 2009

    Posted 01 Feb 2011 Link to this post

    Hello,

    As far as I'm aware there is no event for this. However, if you are wishing to emulate paging, then there is an article here that descibes emulating paging with LINQ and 1 million records.

    Hope that helps
    Richard
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  4. Svett
    Admin
    Svett avatar
    728 posts

    Posted 03 Feb 2011 Link to this post

    Hi VSmirk,

    I am not able to reproduce the issue. The event is fired on my side. I would kindly ask you to open a new support ticket where you can send a sample project where your scenario is illustrates.

    Kind regards,
    Svett
    the Telerik team
    Q3’10 SP1 of RadControls for WinForms is available for download; also available is the Q1'11 Roadmap for Telerik Windows Forms controls.
  5. Jeff
    Jeff avatar
    14 posts
    Member since:
    Aug 2013

    Posted 27 Nov 2014 in reply to Richard Slade Link to this post

    Does anyone know if there's an updated URL for the link Richard posted?
  6. Stefan
    Admin
    Stefan avatar
    2891 posts

    Posted 01 Dec 2014 Link to this post

    Hi,

    The link you are looking for is here: http://blogs.telerik.com/winformsteam/posts/08-09-02/emulating-paging-with-radgridview-for-winforms-and-linq-with-1-million-records.aspx. However, this article is quote outdated. RadGridView now supports paging out of the box. More information about it is available in our documentation: http://www.telerik.com/help/winforms/gridview-paging-overview.html.

    If you need to load great amounts of data, you can look at the following article: http://www.telerik.com/support/kb/winforms/gridview/details/high-performance-with-radgridview-and-virtual-mode-including-filtering-sorting-and-grouping.

    I hope that you find this information useful.

    Regards,
    Stefan
    Telerik
     

    Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.

     
  7. Jeff
    Jeff avatar
    14 posts
    Member since:
    Aug 2013

    Posted 01 Dec 2014 in reply to Stefan Link to this post

    Thank you, Stefan.  At first glance, those articles do look useful.  Regarding the OP's original question, it would sure be nice if the GridView, which "is-a" ScrollableControl, would honour the contract and emit Scroll events.  To load more data is not the only use of that event.
  8. Stefan
    Admin
    Stefan avatar
    2891 posts

    Posted 04 Dec 2014 Link to this post

    Hello Jeff,

    I am glad you find these articles useful.

    As my colleagues Svett mentioned back in 2011, we were not able to replicate a case where the Scroll event will not be fired. I have just tested this again, with our latest version, and the event is triggered correctly.

    Should you have any issues with this event, please get back to us with more details how to replicate the undesired behavior and we will gladly look into it.

    Regards,
    Stefan
    Telerik
     

    Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.

     
  9. Jeff
    Jeff avatar
    14 posts
    Member since:
    Aug 2013

    Posted 05 Dec 2014 in reply to Stefan Link to this post

    Hi Stefan,

    Thank you again.  The simple thing I overlooked in the thread above was the property change from "GridElement" to "TableElement".  I don't know exactly when it changed, but it appears that in 2009 it was called "GridElement" and skipping forward to 2011 it was called "TableElement".  I just overlooked that switch, but I'm able to use the event as expected now.

    Thank you.
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