Symfony 2 : bind request to form object containing objects - forms

Question

I am trying to do something that I am not sure it is possible to do.
Here is my form object :
class DeclarationForm {
private $string1;
private $paramObject;
}
Here is the Param Object :
class Param {
private $id;
private $name;
}
I wanted the form to display a select for the 'ParamObject' field in the creation phase
public function buildForm(FormBuilderInterface $builder, array $options) {
$phase = intval($this->options['phase']);
if($phase === 0) {
$params_qualities = $this->options['params_qualities'] // this is an array of Param Objects;
$qualities = new ObjectChoiceList($params_qualities, 'name', array(), null, 'id');
$builder->add('paramObject', 'choice', array(
'required' => true,
'choice_list' => $qualities
));
}
...
}
it works fine and of course, when I submit the form only the id of the selected option is put in the request.
The problem is when I use $form->handleRequest($request); in the controller, it tries to put a string (the id value) in a Param Object of my DeclarationForm.
Is it even possible to get the label of the selected option in the request to populate the Param Object when handleRequest tries to bind the request to the object ?
How to do that ?
Thank you

Answer 1

It is possible, but not with just one Form. In Symfony, each individual Form has a single backing data object (if at all), and each HTML field corresponds to a single member of that object (apart from special cases like dates and entities). However, one of the Field Types you can use is Form, representing a child Form with its own data object.
In your case, that means doing something like this:
class DecorationFormType {
public function buildForm(FormBuilderInterface $builder, array $options) {
$phase = intval($this->options['phase']);
if($phase === 0) {
//Add child form for param; pass options (with dropdown info) in
//By default fieldname needs to match object member
$builder->add('paramObject', new ParamType(), ['options' => $options] );
}
...
}
}
class ParamType {
public function buildForm(FormBuilderInterface $builder, array $options) {
$params_qualities = $this->options['params_qualities'] // this is an array of Param Objects;
$qualities = new ObjectChoiceList($params_qualities, 'name', array(), null, 'id');
//By default fieldname needs to match object member
$builder->add('id', 'choice', array(
'required' => true,
'choice_list' => $qualities
));
...
}
}
Then in the Controller
public parameterAction() {
//Get param options somehow and stick in $options
$paramForm = $this->createForm(new DecorationFormType(), $decorationForm, $options);
}
So basically you create your main Form as normal, and in that Form one of the Fields it adds is the subform. The name of that Field needs to match a public property or getter on the DeclarationForm class so that it can find the data object (you can override this in the options). You set data_class on each Form appropriately.
Apologies if that's not quite right, I've not tested it and I'm more used to using Collections (which is where you have potentially several of a given subform, depending on the data).
Generally the advice is to use Form Events to manipulate what Fields get added to Forms (your Param one only gets added if phase==0 for example), but I don't think it matters if you're only going to use the Form once.
I wouldn't normally have used the Form Options to pass dropdown info in to the Form, but that might just be me, not sure what best practice is - on the one hand you'd be mixing your own stuff up with a whole load of fixed Symfony keys, but on the other it's a handy place to put it! I've used members of my data objects for that kind of thing in the past.
As for your question about getting the label back from the HTML form - you can't do that as is, because as you've seen the only thing the Request contains is the ID. I can imagine solving this several ways:
Use the labels as the dropdown keys (if they're unique)
Remap IDs to labels in the Param object somehow, give it the list of options so when you go getName() or whatever it can magically give you what you want
Just accept that you get an ID back and look up what it means when you use it!