2 Replies Latest reply on Apr 20, 2010 10:14 AM by acgrama

    valueChangeListener reacting only on second try?

    acgrama
    acgrama Apr 19, 2010 5:12 PM

      Hello all,


      I have two drop down lists and I want to load the second one with values based on what was chosen in the first one. However, the onchange event is only detected the second time I change the selection!


      The relevant bits of the xhtml:



      <ui:define name="body">
<h:form>
<h:panelGrid columns="2">
    <rich:inplaceSelect value="#{searchSimilarProblems.problematicArea}" 
       valueChangeListener="#{searchSimilarProblems.problematicAreaValueChanged}" defaultLabel="Click here to select">
        <f:selectItems value="#{searchSimilarProblems.problematicAreas}"/>
        <a4j:support event="onchange" reRender="items"/>
    </rich:inplaceSelect>
    <a4j:outputPanel id="label">
        <h:outputText value="Choose concrete product:" />
    </a4j:outputPanel>  
    <a4j:outputPanel id="items">
        <rich:inplaceSelect value="#{searchSimilarProblems.impactedElement}" defaultLabel="Click here to select">
            <f:selectItems value="#{searchSimilarProblems.impactedElements}"/>
        </rich:inplaceSelect>
    </a4j:outputPanel>
</h:panelGrid>
</h:form>
</ui:define>




      And in my bean I have



      public void problematicAreaValueChanged(ValueChangeEvent event)





      The problem is that problematicAreaValueChanged() is invoked only when I modify the value of the problematic area for the second time (and I get a null for the event's oldValue).


      Does anyone have an idea regarding what might be wrong? Thanks in advance! I am using Seam 2.2.0 and Java 1.6.0.19, if that helps.
      --Cristina.

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        • 1. Re: valueChangeListener reacting only on second try?
          gaborj
          gaborj Apr 19, 2010 11:07 PM (in response to acgrama)

          Hi,


          I think a valueChangeListener is not what you want to use here. Read more about it e.g. here...


          But you already have an 


          <a4j:support event="onchange" reRender="items"/>



          try to update your model by this event like:


          <a:support event="onchange" 
    action="#{yourBean.yourMethod()}" 
    reRender="items"  
    ajaxSingle="true" 
    eventsQueue="yourQ"
    requestDelay="100"/>

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          • 2. Re: valueChangeListener reacting only on second try?
            acgrama
            acgrama Apr 20, 2010 10:14 AM (in response to acgrama)

            Thanks for the suggestion! I will try it out.


            In the meantime I managed to make it do what I need by using the event onviewactivated. (With event onchange, it seemed like the event's newValue was constantly one step behind: I had two choices in my first drop down list, when I chose 1, newValue was still 2, then I chose 2 and newValue would become 1, then choosing 1 again made newValue become 2 and so on...)

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