<f:ajax>在PrimeFaces组件上不起作用

Question

I trying to use the onChange event of selectOneMenu , but it doesn't work and the component is not displayed when I add onChange attribue.

Can someone tell me how can I handle the onChange event of <p:selectOneMenu> ?

Here is my view:

<p:selectOneMenu id="service" filterMatchMode="startsWith">  
    <f:selectItem itemLabel="Selectionner un Service : "  />  
    <f:selectItems value="#{newOpProgramme.listeSevice}" var="service" itemValue="#{service.serviceId}" itemLabel="#{service.serviceNom}"/>
    <f:ajax event="change" execute="@this" listener="#{newOpProgramme.serviceChange()}" render="nomCdp"/>
</p:selectOneMenu>

And here is the <f:ajax listener> method in a request scoped bean:

public void serviceChange() {
    System.out.println("change");
}

When I change the menu, however, nothing is been printed.

How is this caused and how can I solve it?

Answer 1

First of all, onChange is the wrong event name. It's change . Secondly, if you intend to call the HTML attribute name, onChange is also the wrong attribute name. It's onchange .

Coming back to your concrete problem; the standard JSF <f:ajax> is not compatible with PrimeFaces components. You should be using PrimeFaces own <p:ajax> instead.

<p:selectOneMenu ...>
    ...
    <p:ajax listener="#{newOpProgramme.serviceChange()}" update="nomCdp" />
</p:selectOneMenu>

Note that I omitted the event and the process attributes. They both have already the right default value of valueChange and @this respectively.

See also:

• What values can I pass to the event attribute of the f:ajax tag?
• Understanding PrimeFaces process/update and JSF f:ajax execute/render attributes

Answer 2

When I want to update something after change in selectOneMenu, I use <f:ajax> tag inside selectOneMenu like this:

  <h:selectOneMenu value="#{bean.selected}" >
... select items here
     <f:ajax event="change" execute="@this" render="search" />
  </h:selectOneMenu>

Where search is the Id of the object you want to update.

Other solution is that you should try onchange not onChange .

Answer 3

<p:selectOneMenu value="#{someBean.myAttr.id}" valueChangeListener="#someBean.mySelectioMethodListener}">
    <f:selectItems value="#{someBean.listAttrs}" var="item"
        itemLabel="#{item.name}" itemValue="#{item.id}" />
    <p:ajax process="@this" update="someElementId" />
</p:selectOneMenu>

You must put an Id for <f:selectItems /> and set your selection on backing bean side by posted ajax itemValue (id).

Server side method bean without a converter:

public void mySelectionMethodListener(ValueChangeEvent event) {
ApplicationContext context = FacesContextUtils.getWebApplicationContext(FacesContext.getCurrentInstance());        
    SomeBeanDao someBeanDao = (SomeBeanDao) context.getBean(SomeBeanDao.class);
    myAttr = someBeanDao.byId((Long) event.getNewValue());
    System.out.println("value changed...");
}