JSF ReRender support with selectBooleanCheckbox

问题:

I have a JSF page on which I want to have a checkbox that, when clicked, will add/remove certain other form fields from the page. Here is the (simplified) code I currently have for the checkbox:

<h:selectBooleanCheckbox title="showComponentToReRender" value="#{backingBean.showComponentToReRender}">
    <a4j:support event="onsubmit" reRender="componentToReRender" />
</h:selectBooleanCheckbox>

Here is the code for the component I want to hide:

<h:selectOneMenu id="componentToReRender" value="#{backingBean.value}" rendered="#{valuesList.rowCount>1 &amp;&amp; backingBean.showComponentToReRender}">
   <s:selectItems value="#{valuesList}" var="value"/>
</h:selectOneMenu>

Currently, clicking the checkbox does nothing; that "selectOneMenu" will not go away. What am I doing wrong?

回答1:

You need to wrap the componentToReRender in either:

<h:panelGroup id="componentToReRenderWrapper">

or

<a4j:outputPanel id="componentToReRenderWrapper">

So, effectively you will have:

<h:panelGroup id="componentToReRenderWrapper">
    <h:selectOneMenu id="componentToReRender" value="#{backingBean.value}" rendered="#{valuesList.rowCount>1 &amp;&amp; backingBean.showComponentToReRender}">
       <s:selectItems value="#{valuesList}" var="value"/>
    </h:selectOneMenu>
</h:panelGroup>

and change the reRender="componentToReRenderWrapper" in case you use panelGroup, or remove that attribute, in case you use outputPanel.

Found the exact explanation in the RichFaces docs:

Most common problem with using reRender is pointing it to the component that has a "rendered" attribute. Note, that JSF does not mark the place in the browser DOM where the outcome of the component should be placed in case the "rendered" condition returns false. Therefore, after the component becomes rendered during the Ajax request, RichFaces delivers the rendered code to the client, but does not update a page, because the place for update is unknown. You need to point to one of the parent components that has no "rendered" attribute. As an alternative, you can wrap the component with layout="none" .

回答2:

Don't forget to set ajaxRendered="true" on the a4j:outputPanel