Dear Sven,
thank you so much for pointing me into the right direction!! Indeed,
I'm interested in your 2nd approach. I tried to go the direct way from
DCC --> LDM. But as you said, the DCC model value should be the same as
the ones stored in the choices. And therefore the way DCC -->
Model<String> --> LDM is the right one.
You made my day ... Thanks!!
Walter
On Fri 22 Jun 2012 03:10:27 EST, Sven Meier wrote:
> Hi Walter,
>
> you should keep the type of the DDC's model object the same as the
> type of choices.
>
> Either use full blown objects:
>
> IModel<My> myModel = new MyLDM(...);
>
> add(new DropDownChoice<My>( "idSelection", myModel, new
> PropertyModel<My>(Cases, "allCases")) {
> @Override
> protected void onSelectionChanged(My newSelection) {
> // nothing to do for the selection since the selected
> choice is already pushed into myModel.
> }
> });
>
> Or if it is to expensive to load all objects go for Strings only:
>
> MyLDM myModel = new MyLDM(...);
>
> IModel<String> stringModel = new IModel() {
> public void setObject(String value) {
> myModel.setId(value);
> }
>
> public String getObject() {
> return myModel.getId();
> }
> };
>
> add(new DropDownChoice<String>( "idSelection", stringModel, new
> PropertyModel<String>(Cases, "allCases")) {
> @Override
> protected void onSelectionChanged(Object newSelection) {
> // nothing to do for the selection since the selected
> choice is already pushed into myModel.
> }
> });
>
> See how myModel adapts MyLDM to Strings.
>
> BTW changing model references is a recipe for disaster in most cases:
>
> myLDM = new MyLDM((String) newSelection);
>
> You never know who holds a reference to the old model and thus misses
> the update (as the DropDownChoice in your code).
>
> Hope this helps
> Sven
>
>
>
>
>
> On 06/21/2012 10:11 AM, Walter Rugora wrote:
>> Hi there,
>>
>> I've a LoadableDetachableModel which works pretty much like all LDM
>> examples. There is an overwritten load method that returns an object
>> based on an id member which is set via the constructor.
>> In addition there is a DropDownChoice added to the WebPage (no form is
>> used). The choices object is a model which returns a list of Strings.
>>
>> Each string of that list represents an id which is necessary to retrieve
>> an object.
>> And here the problem start. I'd like to use the LDM to return an object
>> based on the selected id of the DDC.
>>
>> Beside the component id and the choices list (IModel), I'd like to
>> utilize the third mode parameter (IModel). From my understanding, model
>> allows to preselect an item in the DCC. But as well the item selected by
>> the user is that written back into Model. Very convenient!
>> But in my case, since choices is based on a list of Strings, only a
>> String is written to the model.
>>
>> So, I don't know how to connect the new value of my DDC model with the
>> LDM that I use.
>>
>> As well, I overwrite the onSelectionChanged method of the DDC. Within
>> this method I try to assign a new LDM with the newSelection value as a
>> constructor argument to a global LDM model, but the LDM id member value
>> never changes:
>> public class HomePage extends WebPage{
>> private MyLDM myLDM = new MyLDM("123");
>> ...
>> public HomePage(final PageParameters parameters) {
>> ...
>> add(new DropDownChoice(
>> "idSelection",
>> [a model ... but how to use it to update the LDM id],
>> new PropertyModel(Cases, "allCases")) {
>> @Override
>> protected void onSelectionChanged(Object newSelection) {
>> myLDM= new MyLDM((String) newSelection);
>> }
>> ...
>>
>> I'm very much lost. Maybe my approach is simply wrong. I have the gut
>> feeling that it is easy to solve, but as a beginner I got lost in the
>> model jungle. Get me out there ... please ;)
>>
>> Thanks,
>> Walter
>>
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>
>
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