@DependsOn requires to keep listbox selection twice

answered 2014-11-19 16:02:44 +0800

cyiannoulis
1201 ● 10

The problem is that the toolbarbutton has to be notified either with a @DependsOn or with a @NotifyChange trigger. If you want to eliminate the second list (vm.selectedEntries) from your view model you may use a workaround like the following one:

<window title="Listbox with multiple selections" 
        apply="org.zkoss.bind.BindComposer"
        viewModel="@id('vm') @init('snippets.listboxSelections.LboxVM')" 
        border="none">

    <toolbar>
        <toolbarbutton label="@load(vm.hasSelections ? 'OK' : 'Nothing selected')" 
                   disabled="@load(!vm.hasSelections)" />
    </toolbar>

    <listbox model="@load(vm.listData)" 
             multiple="true" checkmark="true"
             onSelect="@command('items-selected')">

        <listhead>
            <listheader label="Star Wars" />
        </listhead>
        <template name="model" var="person">
            <listitem label="@load(person)" />  
        </template>
    </listbox>

</window>

And the VM:

public class LboxVM {

    private ListModelList<String> listData;

    @Init
    public void init() {

      String[] data = {"Luke Skywalker ", "Darth Vader", "Obi-Wan Kenobi", "Joda"};
      listData = new ListModelList<String>( Arrays.asList(data) );
    }

    @Command("items-selected")
    @NotifyChange("hasSelections")
    public void onItemsSelected() {};

    public boolean getHasSelections() {
        return !listData.getSelection().isEmpty();
    }

    public ListModelList<String> getListData() {
        return listData;
    }

    public void setListData(ListModelList<String> listData) {
        this.listData = listData;
    }
}

As you see the Command("items-selected") is implemented only because we need to make a @NotifyChange back to the status of the toolbarbutton.

Hope that helps

Costas