Virtual scrolling "paging too early"

[-DJ-]

Hi guys.

I'm trying to implement the most basic version of virtual scrolling. (http://www.telerik.com/help/aspnet-ajax/grid-virtual-scrolling.html)

It works as intended, as long as I'm using a very small pagesize (no larger than 10 basically), or if I'm setting the height of the grid high enough, so that it basically displays all records (of the current page) with very little scrolling.

But that's the only time when it works correctly on my end. As soon as I increase the pagesize of the grid and keep the height of it "normal", it starts paging too early and "skipping" rows.

Let's say I'm binding 200 records to the grid, and using a pagesize of 100, sorting the grid desc by id.

I scroll down, but when I reach approximately the row with id of 140, the grid pages to the second page, and shows me correctly the second page of the grid.

But I can never access the rows between 100 and 140...

Any idea why this is happening?

Regards,
-DJ-

[Konstantin Dikov]

Hello Daniel,

I have tried to reproduce one of the mentioned issue, but to no avail. Please refer to the attached sample page and see what differs in your project.

About the issue with records after the 100th row, this is due to the following condition in the JavaScript code:

if (currentlyDisplayedRecords < 100) {
    $find("<%= RadAjaxManager1.ClientID %>").ajaxRequest("LoadMoreRecords");
}

Please note that you will have to change "100" with your current items count in order to retrieve all items with the scrolling.

Hope this helps.

 

Regards,
Konstantin Dikov
Telerik