Hi Iain,
I would do it like this, with a FormValidator. I moved the minimum length
validation also to the formValidator, because doing it with a
MinimumLenghtValidator would trigger it before the formValidator executes,
and may raise errors when the input is not valid (i.e. not mandatory) :
private class TestForm extends Form {
IModel modelAlways;
IModel modelCheckOptional;
IModel modelOptional;
public TestForm(String id) {
super(id);
modelAlways = new Model("");
modelCheckOptional = Boolean.FALSE;
modelOptional = new Model("");
final TextField alwaysTextfield = new TextField("always", modelAlways);
alwaysTextField.setRequired(true);
add(alwaysTextField);
final CheckBox useOptionalCheck = new CheckBox( "useOptional",
modelCheckOptional);
add( useOptionalCheck );
final TextField optionalTextField = new TextField("optional",
modelOptional);
add(optionalTextField);
add(new IFormValidator(){
protected FormComponent getDependentFormComponents(){ return null; }
public boolean validate(Form f){
if (Boolean.TRUE.equals(useOptionalCheck.getConvertedInput()){
String optionalValue =
optionalTextField.getConvertedInput();
if (Strings.isEmpty(optionalValue ){
error ("field optional is required");
}
else if (optionalValue.length < 3){
error ("optional value's length must be at least 3);
}
}.
}
});
Cheers,
Xavier
2010/6/2 Iain Reddick <[email protected]>
> Here's some example code (wicket 1.3.x):
>
> Java:
>
> private class TestForm extends Form {
>
> private String always;
> private boolean useOptional = false;
> private String optional;
>
> public TestForm(String id) {
> super(id);
>
> add( new TextField("always", new PropertyModel(this,
> "always")).setRequired(true) );
> final CheckBox useOptionalCheck = new CheckBox( "useOptional", new
> PropertyModel(this, "useOptional") );
> add( useOptionalCheck );
> add( new TextField("optional", new PropertyModel(this, "optional")) {
> @Override
> public boolean isRequired() {
> return
> ((Boolean)useOptionalCheck.getConvertedInput()).booleanValue();
> }
> }.add(MinimumLengthValidator.minimumLength(3)) );
> }
>
> }
>
> Markup:
>
> <form wicket:id="testForm">
> <input wicket:id="always" type="text" />
> <input wicket:id="useOptional" type="checkbox" />
> <input wicket:id="optional" type="text" />
> <input type="submit" />
> </form>
>
> How can I express that I want the optional text field to only be used when
> the checkbox is selected?
>
> ----- Original Message -----
> From: "Igor Vaynberg" <[email protected]>
> To: [email protected]
> Sent: Wednesday, 2 June, 2010 4:00:57 PM
> Subject: Re: Show/hide form components best practice
>
> if the form contains all the state then the answer is simple: write a
> bit of javascript that does it for you.
>
> -igor
>
> On Wed, Jun 2, 2010 at 2:53 AM, Iain Reddick
> <[email protected]> wrote:
> > That's just a server round-trip on client-side state changem, which is
> > basically (1) in my initial list.
> >
> > Basically, this type of form behaviour is very common and the question
> > of how to implement it with Wicket has been raised by every developer
> > I know
> > who has worked with the framework.
> >
> > I know that Wicket generally works best when you round-trip
> > client-side state changes to the server, but I think that in this
> > situation it is silly,
> > as the submitted form contains all the required state.
> >
> > Jeremy Thomerson wrote:
> >>
> >> return true from wantOnSelectionChangedNotifications and put your
> >> visibility changing code in onSelectionChanged
> >>
> >>
> >> <
> http://wicket.apache.org/docs/1.4/org/apache/wicket/markup/html/form/CheckGroup.html#wantOnSelectionChangedNotifications()<http://wicket.apache.org/docs/1.4/org/apache/wicket/markup/html/form/CheckGroup.html#wantOnSelectionChangedNotifications%28%29>
> >
> >>
> >>
> http://wicket.apache.org/docs/1.4/org/apache/wicket/markup/html/form/CheckGroup.html#wantOnSelectionChangedNotifications()<http://wicket.apache.org/docs/1.4/org/apache/wicket/markup/html/form/CheckGroup.html#wantOnSelectionChangedNotifications%28%29>
> >>
> >> On Tue, Jun 1, 2010 at 5:37 AM, Iain Reddick
> >> <[email protected]>wrote:
> >>
> >>
> >>>
> >>> Say I have a form with a check box that, when checked, shows some
> >>> other field (i.e. it controls the visibility of other form
> >>> components).
> >>>
> >>> What is the best approach to handling this?
> >>>
> >>> From what I understand, you have 3 options:
> >>>
> >>> 1. Add ajax behaviour to the check box (re-render relevant
> >>> components). 2. Add javascript from the Java code (e.g. add some
> >>> kind of show/hide
> >>> behaviour). 3. Add javascript directly to the HTML.
> >>>
> >>> What are peoples experiences of the 3 methods, and which is best?
> >>>
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> >>> For additional commands, e-mail: [email protected]
> >>>
> >>>
> >>>
> >>
> >>
> >>
> >
> >
>
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