final TestItem itemModel = (TestItem) item.getModelObject();
^ on this line you retrieve the object from the model, you then use
this reference inside the onclick() which is called during another
request. since you use the model object reference directly it is not
loaded from the model.
my code, on the other hand, never keeps a direct reference to the
model object, instead it retrieves it from the model inside onclick()
-igor
On Thu, Oct 2, 2008 at 10:10 AM, Jürgen Lind <[EMAIL PROTECTED]> wrote:
> Igor Vaynberg wrote:
>>
>> your link works on the object and not on the model, instead
>>
>> add(new link("delete", item.getmodel()) { onclick() {
>> delete(getmodelobject()); }});
>>
>
> Thank you for your quick reply.
>
> Well the code is roughly the same(?) as in Listing 5.12 of WiA and there
> a custom Model is used to illustrate the solution. However, I thought my
> test would show me the problem first... Using your code above, the
> effect is as expected, i.e. the "wrong" (new) item is returned to be
> deleted.
>
> Now, the question is, what is wrong with my first implementation?
> It would seem that the problem that is solved using a custom ItemModel
> does not even occur. Or does that code prevent wicket from effectively
> detaching model objects and should thus be avoided? What would be the
> best practice here?
>
>
> J.
>
>> -igor
>>
>> On Thu, Oct 2, 2008 at 9:04 AM, Jürgen Lind <[EMAIL PROTECTED]>
>> wrote:
>>>
>>> Hi there,
>>>
>>> I have been struggling for some time now to understand how
>>> LoadableDetachableModel and a ListView work together. The starting point
>>> was Chapter 5.5.2 of "Wicket in Action" where it is recommended to
>>> provide
>>> your own ItemModel if the underlying list changes frequently. To try out
>>> how Wicket behaves without such a custom ItemModel, I wrote the following
>>> Test:
>>>
>>> <body>
>>> <em wicket:id="listview">
>>> <span wicket:id="label"></span><a wicket:id="delete">delete</a>
>>> </em>
>>> </body>
>>>
>>>
>>> LoadableDetachableModel model = new LoadableDetachableModel() {
>>>
>>> @Override
>>> protected Object load() {
>>> System.out.println("load");
>>> return Arrays.asList(new TestItem[] {
>>> new TestItem("a" + Math.random()),
>>> new TestItem("b" + Math.random()),
>>> new TestItem("c" + Math.random()) });
>>> }
>>>
>>> protected void onDetach() {
>>> System.out.println("detach");
>>> }
>>>
>>> };
>>>
>>> ListView listview = new ListView("listview", model) {
>>> protected void populateItem(ListItem item) {
>>> final TestItem itemModel = (TestItem) item.getModelObject();
>>> item.add(new Label("label", itemModel.toString()));
>>> item.add(new Link("delete") {
>>>
>>> @Override
>>> public void onClick() {
>>> System.out.println("Delete " + itemModel);
>>> }
>>> });
>>> }
>>> };
>>>
>>> add(listview);
>>>
>>>
>>> Now, I would expect that when I hit the "delete" link, Wicket would call
>>> the
>>> "load" Method of the LoadableDetachableModel before printing "Delete..."
>>> as
>>> the
>>> default implementation will use the index and the list to determine the
>>> item
>>> to
>>> delete. To my surprise, however, the "Delete..." message is printed with
>>> the
>>> correct item and the "load" Method is called afterwards. In my
>>> understanding,
>>> this contradicts the idea of the LoadableDetachableModel since Wicket
>>> seems
>>> to
>>> have a copy of the original list somewhere so that it can determine the
>>> list
>>> item on which the action was invoked before loading the underlying list.
>>>
>>> Can someone spot my mistake?
>>>
>>> Thanks,
>>>
>>> J.
>>>
>>> --
>>> Dr. Jürgen Lind
>>> iteratec GmbH Fon: +49 (0)89 614551-44
>>> Inselkammerstrasse 4 Fax: +49 (0)89 614551-10
>>> 82008 Unterhaching Web: www.iteratec.de
>>>
>>> Sitz und Registergericht der iteratec GmbH: München HRB 113 519
>>> Geschäftsführer: Klaus Eberhardt, Mark Goerke, Inge Hanschke, Ralf Menzel
>>>
>>>
>>> ---------------------------------------------------------------------
>>> To unsubscribe, e-mail: [EMAIL PROTECTED]
>>> For additional commands, e-mail: [EMAIL PROTECTED]
>>>
>>>
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: [EMAIL PROTECTED]
>> For additional commands, e-mail: [EMAIL PROTECTED]
>>
>
> --
> Dr. Jürgen Lind
> iteratec GmbH Fon: +49 (0)89 614551-44
> Inselkammerstrasse 4 Fax: +49 (0)89 614551-10
> 82008 Unterhaching Web: www.iteratec.de
>
> Sitz und Registergericht der iteratec GmbH: München HRB 113 519
> Geschäftsführer: Klaus Eberhardt, Mark Goerke, Inge Hanschke, Ralf Menzel
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: [EMAIL PROTECTED]
> For additional commands, e-mail: [EMAIL PROTECTED]
>
>
---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
