Dependent combo boxes using webservice

Question

Hi All,
I'm trying to create a depended combo boxes using af:selectOneChoice, using webservice datacontrol. When i try to change the value of the first combo box which has hard coded values (eg. Continent), The depended combo box (eg.Country) is empty. (which is returned via webservice) When i again change the value of the first combo box, I get the corresponding values(Countries) generated. The very first time when a value is selected is not binded to the model. Why is this happening and how to overcome this issue. I tried using the value change listener and assigned the current value to binding but there was no change in the behaviour.

Answer 1

Thanks for your response Frank. The Sample worked fine. But when i try to implement the same i ran into issues.
First, I created a combo box for continents and a managed bean.
<af:selectOneChoice label="Region" id="soc1" autoSubmit="true"
                              valueChangeListener="#{locateBean.setRegion}">
            <af:selectItem label="Asia" value="Asia" id="si3"/>
            <af:selectItem label="Europe" value="Europe" id="si2"/>
            <af:selectItem label="NA" value="NA" id="si1"/>
          </af:selectOneChoice>Then I created a combo box for countries using the webservice data control.
          <af:selectOneChoice value="#{bindings.Country.inputValue}"
                              label="Country"
                              required="#{bindings.Country.hints.mandatory}"
                              shortDesc="#{bindings.Country.hints.tooltip}"
                              id="soc2" partialTriggers="soc1">
            <f:selectItems value="#{bindings.Country.items}" id="si4"/>
          </af:selectOneChoice>In the managed bean as
    public void setRegion(ValueChangeEvent event) {
        this.region = (String)event.getNewValue();
    }1. When i run and select an continent, the values are not getting populated in the country combo box. If i refresh the page or select another value for the continent, then its is getting populated.
2. When i tried to execute the operation manually at pagedef on value change event,
        OperationBinding operBinding = getBindings().getOperationBinding("GetCountryList");
        operBinding.execute();I'm getting an warning as <FacesCtrlListBinding> <getInputValue> ADFv: Could not find selected item matching value Afghanistan of type: java.lang.String in the list-of-values.Why the value binded to the managed bean or model is not getting updated for the first time. Is this the expected behavior.