Preventing Postback on Node Expand

[SHP]

Is there any way to prevent the postback when expanding a node?  It seems like this should be unnecessary once the control is data-bound.  Thanks.

[Gimmik]

Hi Cevin,

I believe your assumption about data-binding is incorrect. Expanding a RadTreeList is similar to paging a RadGrid. The postback is required because only the data currently being displayed is bound to the control. Imagine having a List of 100 items, each with 100 children, and each of those with 50 children. It would take a very long time to load the RadTreeList when you first navigate to the page.

To minimize the impact of the postback I suggest you fully ajaxify your RadTreeList. That will ensure that only the RadTreeList is posting back to the server, not the whole page.

Here is a helpful document about ajaxifying your control:
http://www.telerik.com/help/aspnet-ajax/ajax-ajax.html

Hope this helps!
-Gimmik

[SHP]

Thanks for your response.  I should have been more specific (apologies), but I have already AJAX-ified the control.  I was surprised to find that AJAX calls were still being made when expand/collapse requests were initiated.  I guess it is by design due to the performance implications you hinted at.  Still, like paging, I believe that this should a property of the control that the developer should be able to turn ON and OFF (dealing with the consequences in performance, of course).  There are probably some technical hurdles with that potential feature that the Telerik design team encountered and decided to punt on.  Hopefully they'll reconsider that in the future.

I guess I'll have to compromise by pre-exanding the TreeList using the .ExpandToLevel() function, which makes the UI a little more busy but prevents some hits to the web server and database as the user drills down into the details.

Thanks again!

[Tsvetina]

Hi Cevin,

The RadTreeList postbacks on node expand because with its current available load mode, the children items of an unexpanded parent are not created until the parent is expanded. This, as previously mentioned, is done as a performance optimization. In case many customers demand the client load mode (similar to grid hierarchy) our developers will consider implementing it for the treelist.

Additionally, keep in mind that in order for the treelist to expand client-side, again its whole structure will be sent back from the server (similarly to the case where you expand the whole control), so there will still be a lot of content to render on the page.

Best wishes,
Tsvetina
the Telerik team

[Vishal]

I want to have mutiple check box . One for allow and another for deny. This is not selection. So when I select any of these checkbox and and expand and contract the node, the checked ones are again unchecked.
Please let me  know how to maintain the state of checkboxes on collapse and expand of node.

Please reply asap.

[Tsvetina]

Hello Vishal,

Since on expand and collapse the treelist is rebound and its items are recreated, you would need to manually persist your custom selection. You could recognize the items by DataKeyValue and use it to keep their selection in a collection in the Session or the ViewState.

Best wishes,
Tsvetina
the Telerik team

[Bogey]

Was the functionality to optionally expand the treelist on the client ever implemented? If so, please advise - I haven't found it yet.   We often bind our custom collections to radtreeview and radtreelist. With relatively small trees, it would be nice to have the expand client-side option on the radtreelist, similar to If the RadTreeView; i.e., it would simplify managing the state of both our collection objects and the control if we didn't have to deal with the 'expand postback'.

Thanks

[Maria Ilieva]

Hello Dan,

The described feature is still not implemented in the RadTreeList control. The control's structure requires postback for expanding the items and creating client approach for this functionality is a lot of effort and time consuming task. Our dev team has this request in mind and in case any progress on its is made I will get back to you with our final decision.

Regards,
Maria Ilieva
Telerik

[juansimon]

It would be nice if the developer team could take this behavior in the next release.

[Maria Ilieva]

Hi Juan,

 The mentioned feature is not added in the planning for the next official release due to a lot of other important and complex functionality we should implement. However as I mentioned our dev team take your requests in mind and we hope this functionality will be implemented in some of the releases in 2014.

Regards,
Maria Ilieva
Telerik

[Jan]

Is there any news in January 2015?

[Maria Ilieva]

Hi,

Unfortunately the required feature is still not implemented into the RadTreeList control. For now we are keeping it implementation on hold as it will cause a big code revision and will lead to a lot of breaking changes in the control which we are trying to avoid.
As soon as such functionality is added into our To Do List for some for some of the upcoming resales we will inform the community.

Regards,
Maria Ilieva
Telerik

 

 

[yogesh]

Hi Admin,

Is there any solution on above issue please reply its very urgent.

Thanks in advance.

 

 

[juansimon]

Hi Telerik Team,

This functionality would aggregate a lot of value to the RadTreeList.  I will explain you why it is important. In order to prepare the information to give it to the TreeList, it is necessary to make a lot of hierarchical calculations that consume a lot of CPU and memory resources.  It causes that any server could be busy doing the same complex calculations with each click expanding any level. If you have a lot of users that expands a node of the tree, the server could crash. I prefer,  RadTreeList had all the information one time to prevent making unnecessary recalcularions with every click. 

I like Telerik components, but this issue make me to search another tree component in the market.  Please reconsider this functionality in your next version of your RadTreeList.

 

thanks

Juan Viteri

 

 

[Maria Ilieva]

Hello Juan,

We do not have plans to implement client side node expanding mode in the RadTreeList control for ASP .NET AJAX. However Telerik provides alternative component that will fit perfectly to your requirements and namely the Kendo UI TreeLIst component.
See the online demos below for more information on this widget:
http://demos.telerik.com/kendo-ui/treelist/index

Regards,
Maria Ilieva
Telerik