ZK Developer's Reference/Performance Tips/Listbox, Grid and Tree for Huge Data/Turn on Render on Demand

This documentation is for an older version of ZK. For the latest one, please click here.

[Enterprise Edition]
[Since 5.0.0]

With Enterprise Edition, you can enable Render on Demand for Grid and Listbox to boost performance in showing huge data. Grid and Listbox will load only the necessary data chunk from associated ListModel, render required Row(s)/Listitem(s) in server, then create only required corresponding widgets and render the DOM elements really needed in browser. It improves the performance and saves memory significantly in both server and browser sides.

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ROD: Grid

If you want to enable Grid ROD for the whole application, you can specify a library property called grid with true. For example, specify the following in zk.xml:

<library-property>
	<name>org.zkoss.zul.grid.rod</name>
	<value>true</value>
</library-property>

Or, if you prefer to enable it for a particular page, then specify true to a page's attribute called rod, such as

<custom-attributes org.zkoss.zul.grid.rod="true" scope="page"/>

Or, if you prefer to enable it for all descendant grids of a particular component, then specify true to the component's attribute. And, you can enable it for a subset of the descendant grids. For example,

<window>
  <custom-attributes org.zkoss.zul.grid.rod="true"/> <!-- enable it for descendant grids of window -->
  <grid ...>
    ..
  </grid>
  <div>
    <custom-attributes org.zkoss.zul.grid.rod="false"/> <!-- disable it for descendant grids of div -->
      <grid ...>
        ..
      </grid>
      ..
  </div>
</window>

Note that Grid ROD is not working unless the Grid is configured with a limited view port; i.e. you have to set height or vflex attribute of the Grid or set the Grid to paging mold so the user see only a portion of the content of the Grid.

ROD: Listbox

If you want to enable Listbox ROD for the whole application, you can specify a library property called rod with true. For example, specify the following in zk.xml:

<library-property>
	<name>org.zkoss.zul.listbox.rod</name>
	<value>true</value>
</library-property>

Or, if you prefer to enable it for a particular page, then specify true to a page's attribute called rod, such as

<custom-attributes org.zkoss.zul.listbox.rod="true" scope="page"/>

Or, if you prefer to enable it for all descendant listboxs of a particular component, then specify true to the component's attribute. And, you can enable it for a subset of the descendant listboxs. For example,

<window>
  <custom-attributes org.zkoss.zul.listbox.rod="true"/> <!-- enable it for descendant listboxs of window -->
  <listbox ...>
    ..
  </listbox>
  <div>
    <custom-attributes org.zkoss.zul.listbox.rod="false"/> <!-- disable it for descendant listboxs of div -->
      <listbox ...>
        ..
      </listbox>
      ..
  </div>
</window>

Note that Listbox ROD is not working unless the Listbox is configured with a limited view port; i.e. you have to set height, vflex, or rows attribute of the Listbox or set the Listbox to paging mold so the user see only a portion of the content of the Listbox.