Question

I am using wicket’s CheckBoxMultipleChoice to let the user set a list of options. so far it works fine. but then i want to add a “check all” check box that checks all the options in the CheckBoxMultipleChoice and I am having problems with that.

here is my initial code

ArrayList<String> chosen;
List<String> choices = Arrays.asList(new String[]{"Train", "Bus", "Car"});  
CheckBoxMultipleChoice myCheck = new CheckBoxMultipleChoice("transport", new Model(chosen), choices)); 
myCheck.setOutputMarkupId(true);
form.add(myCheck);

on submit i print out the values of chosen and its “Bus”, “Car” etc. as expected.

now i am adding a checkbox to check all the choices using ajax:

Boolean checkOrNot;
final CheckBox checkAll = new CheckBox("checkAll", new Model(checkOrNot));  
form.add(checkAll);
checkAll.add(new AjaxFormComponentUpdatingBehavior("onchange") {

    @Override
    protected void onUpdate(AjaxRequestTarget target) {         
        // here i am not able to set the checkboxes 

        // i tried doing this
    chosen.clear();
    chosen.add(new String("Car"));
    chosen.add(new String("Train"));    
        myCheck.modelChanged();

        // i have also tried recreating the multiple choice     
        myCheck = new CheckBoxMultipleChoice<T>("transport", new Model(chosen), choices);

        myCheck.setOutputMarkupId(true);
        target.addComponent(myCgecj);
        target.addComponent(form);          
    }
});

I am running out of ideas and wondering if anyone has any solutions? thanks in advance for any help.

Answer 1

I didn’t (and can’t) try that right now, so this is to be taken with a grain of salt, but couldn’t you use a CheckGroup for that?

From the JavaDoc:

Component used to connect instances of Check components into a group. Instances of Check have to be in the component hierarchy somewhere below the group component. The model of the CheckGroup component has to be an instance of java.util.Collection. The model collection of the group is filled with model objects of all selected Check components.

So a

new Checkgroup("group", choices)

should work for you. No need to reimplement that functionality.

P.S.: I’ll check that as soon as I’ve got the chance to do so…