Help!Updating a SelectOneMenu's choices based on the selection of another SelectOneMenu

[markusnn]

It sounds like a trivial case to accomplish with <a4j:support .../> but I am stuck and panicking.

I need to modify the available selections on a SelectOneMenu(A) based on the selection made in another SelectOneMenu(B).

I have tried to use <a4j:support event="onchange" reRender="..."...../> tag with all possible combinations of immediate="true",

bypassUpdates="true" and ajaxSingle="true" but always get validation errors on (A) whenever my backing bean(request scope)

changes the SelectItems of (A) in the valueChangeListener of (B).

I am starting to think there is something very basic that I have missunderstood here(not much experience with JSF/RichFaces).

Please, can you point me to some similar code doing this or give me a hint or ideas to try.

I'll be happy to follow up with a condensed version of the code if you'd care to take a look.

Desperate & Grateful

[nbelaevski]

Hi,

Check a4j:support examples at livedemo.

[harut]

For your case:

<a4j:keepAlive beanName="myBean"/> //if your bean is in request scope

<h:selectOneMenu id="A" value="...">                      
        <f:selectItems value="#{myBean.selectItemsForA}" />                         
</h:selectOneMenu>

<h:selectOneMenu id="B" value="...">                      
     .........

      <a4j:support event="onchange"
                         actionListener="#{myBean.modifySelectItemsOfA}"
                         reRender="A"/>
</h:selectOneMenu>

---------------------------

public class MyBean {

     private List<SelectItem> selectItemsForA;

     .....................

     public void modifySelectItemsOfA(ActionEvent event) {

          //............. Business logic for changing SelectItems for "A"..................

          selectItemsForA = ...;

     }

}

[markusnn]

Thanks

I guess it is difficult to do this kind of thing with a backing bean that is recreated in every request.

[harut]

I guess it is difficult to do this kind of thing with a backing bean that is recreated in every request.

If you will declare your bean as a4j:keepalive (as I mentioned in my previous post) then your bean will not be recreated in every request while you are in the same page...

[ilya_shaikovsky]

and even more you could define that object should be stored only per ajax requests. So when for example you hitting normal h:command for submitting form - it will behaves as standard request scoped bean.