Performance Issue with Extended Selection Mode

[Samuel]

Hi,
The treeview doesn't handle selecting multiple items well.

I downloaded the source for the "1 Million Items" demo, changed the selection mode to "Extended", and it crashes when trying to select hundreds of items simultaneously (using shift + click).

Virtualization is turned on, but apparently it doesn't know how to virtualize in this case.

Please advise.

[Hristo]

Hello Samuel,

Actually the tree view internally stores some of the selected items (not all). If huge amount of records are selected then there could be fair amount of selected items stored internally in order to maintain certain functionality. Also, selected items require additional processing when they enter or leave the visual area of the screen. So, bigger visible area implies more selected items to be rendered. This could bring to performance issues while scrolling. Do you really need to select so many items?

Regards,
Hristo
the Telerik team

[Samuel]

Yes, I require selecting a several thousand rows. I am using this in a drag/drop scenerio with two treeviews. User is selecting from a list of several thousand names.

Please advise.
Thanks

[Hristo]

Hello Samuel,

Selecting such amount of items is going to slow down the performance. There is already a record in our public issue tracking system about similar issue: http://www.telerik.com/support/pits.aspx#/public/silverlight/2510 

You  can vote for it in order to increase its priority. Meanwhile, is it possible to select not expanded nodes and reduce the number of selected items? Take in mind that dragging and dropping thousands of records may also introduce some performance issues.

Please let us know if you need more info or help about our products.

Kind regards,
Hristo
the Telerik team