DropDownChoice and onSelectionChanged error.

[Altuğ B . Altıntaş]

Hi;
I have a problem with DropDownChoice; The code block is here :

List<Faaliyet>faaliyetListesi = // data comes

 final DropDownChoice<Faaliyet> faaliyetler =
                new DropDownChoice<Faaliyet>("Faaliyetler",
                new Model((Serializable) faaliyetListesi),
faaliyetlerRenderer) {

                    @Override
                    protected boolean wantOnSelectionChangedNotifications()
{
                        return true;
                    }

                    @Override
                    protected void onSelectionChanged(Faaliyet newSelection)
{
                        super.onSelectionChanged(newSelection);
                        PageParameters params = new PageParameters();
                        params.add("ay", finalAy + "");
                        params.add("yil", finalYil + "");
                        params.add("faaliyetId", newSelection.getId() + "");
                        setResponsePage(ActionPage.class, params);

                    }
                };


        add(faaliyetler);



The error message is :

wicketMessage: Method onSelectionChanged of interface
org.apache.wicket.markup.html.form.IOnChangeListener targeted at
component [MarkupContainer [Component id = Faaliyetler]] threw an
exception

Root cause:

java.lang.IllegalStateException: Attempt to set model object on null
model of component: Faaliyetler
     at org.apache.wicket.Component.setDefaultModelObject(Component.java:3038)
     at 
org.apache.wicket.markup.html.form.FormComponent.updateModel(FormComponent.java:1168)
     at 
org.apache.wicket.markup.html.form.DropDownChoice.onSelectionChanged(DropDownChoice.java:158)
     at java.lang.reflect.Method.invoke(Method.java:597)
     at 
org.apache.wicket.RequestListenerInterface.invoke(RequestListenerInterface.java:182)
     at 
org.apache.wicket.request.target.component.listener.ListenerInterfaceRequestTarget.processEvents(ListenerInterfaceRequestTarget.java:73)
     at 
org.apache.wicket.request.AbstractRequestCycleProcessor.processEvents(AbstractRequestCycleProcessor.j

-- 

Any suggestions ?

Altuğ.