value becomes invalid (null) after posting form

[vata2999]

Hi,

I have 2 comboboxes (City, Region) that one of them (region) fills based on another as below

<h:selectOneMenu value="#{instituteHome.instance.city}">
    <s:selectItems value="#{cityQuery.resultList}" var="_city" label="#{_city.name}"/>
    <s:convertEntity />
    <a:support event="onchange" ajaxSingle="true" reRender="cityField" />
</h:selectOneMenu>

<h:selectOneMenu id="cityField" value="#{instituteHome.instance.region}">
    <s:selectItems value="#{regionQuery.resultList}" var="_region" label="#{_region.name}"/>
    <s:convertEntity />
</h:selectOneMenu>

RegionQuery.java

@In(create = true)
InstituteHome instituteHome;

@Override
public List<Region> getResultList(){
   if(instituteHome.instance.getCity() != null){ // after posting form turns into null
          return region where city = instituteHome.instance.getCity()
   }else{
     return null; //this is cause of invalid value 
   }
   
}

if i return super.getResultList() instead of null the problem will be solved but in this case
user can see all regions without selecting a city

I'm wondering why when i select city from combobox the instituteHome.instance.getCity() is not null but after posting form it turns into null

Does anyone know how i can solve this problem ?

Thanks in advanced

[juanmiguelbg]

You can try:

@Override
public List<Region> getResultList(){
   if(instituteHome.instance.getCity() != null){
          return region where city = instituteHome.instance.getCity()
   }else{
     return new ArrayList<Region>(); //this solve for us
   }
   
}

[vata2999]

This generates another problem after u select a value from combobox then post the form value will be lost
and user has to select a value again

try this :

@Override
@Begin(join = true)
public List<Region> getResultList(){
   if(instituteHome.instance.getCity() != null){
          return region where city = instituteHome.instance.getCity()
   }else{
     return null;
   }
   
}

problem solved