LoadOnDemand tree and paging

answered 2023-11-13 14:42:14 +0800

MDuchemin
2480 ● 1 ● 6

Hi Ivan

I think doing what you are explaining is possible. It will require some extra handling, but it should work.

First thing is, you cannot use the default Tree in paging mold. Tree in paging mold will always render "one page worth" of items, regardless of their depth in the tree.

Instead, you will need to use a standalone paging component: https://www.zkoss.org/wiki/ZKComponentReference/Supplementary/Paging

You can put that paging component anywhere in the page, but I assume you'll want to put it on top of, or below the tree. You can then listen to events from the paging component (onPaging event is triggered when the user navigate in the paging), and update your tree structure accordingly.

In regard to the tree structure, it depends on where you data is located. If you want to do something like "always display 20 level-1 children and all of the grandchildren", then you might as well create separate tree models for each ranges (1 to 20, 21-40, 41-60, ... ) and replace the model of the tree component whenever onPaging is triggered on the paging component.

If you are loading the data dynamically from a persistence layer, then the options get more complicated :D but it boils down to building the tree models whenever paging happens.