Symfony 2 : How to handle nested collections in forms

Question

I am trying to create a form that contains nested collections. I don't know how to handle the JS part to display the children collection. Does anybody know how can I do that ?

Here is the code of my forms :

class ParentFormType extends AbstractType 
{

    public function buildForm(FormBuilderInterface $builder, array $options) 
    {   
        $builder
              ->add('case', 'choice', array(
                        'choices'   => array(
                            'case1'   =>  'case1',
                            'case2'   =>  'case2',
                            'case3'   =>  'case3',
                )))
            ->add ('subForm1', 'collection', array (
             'type' => new Sub1FormType(),
             'allow_add' => true,
             'allow_delete' => true,
             'by_reference' => false,
             'prototype' => true,
            ))

    ;

        $builder->add('save',"submit") ;
    }


    public function setDefaultOptions(OptionsResolverInterface $resolver) {
    }

    public function getName() {
        return 'formtestparenttype';
    }
}

class Sub1FormType extends AbstractType 
{

    public function buildForm(FormBuilderInterface $builder, array $options) 
    {   

        $builder
          ->add('fieldSub1',"text" )
          ->add ('childForm1', 'collection', array (
              'type' => new Sub2FormType,
              'allow_add' => true,
              'allow_delete' => true,
              'by_reference' => false,
              'prototype' => true,
          ))
          ;
    }


    public function setDefaultOptions(OptionsResolverInterface $resolver) {

    }

    public function getName() {
        return 'formtestsub1type';
    }
}

class Sub2FormType extends AbstractType 
{

    public function buildForm(FormBuilderInterface $builder, array $options) 
    {   

        $builder
               ->add('fieldSub2',"text" )
          ;
    }


    public function setDefaultOptions(OptionsResolverInterface $resolver) {

    }

    public function getName() {
        return 'formtesttype';
    }
}

The controller :

$form = $this->createForm(new ParentFormType() ) ;
return $this->render('MyBundle:Test:test.html.twig', array(
    'form' => $form->createView()
  ));

And Here; the twig + js part :

{% extends '::base.html.twig' %}
{% block content %}

{{ form_start(form) }} 
    <h3>Tags</h3>
    <ul class="collectionHolder" data-prototype="{{ form_widget(form.subForm1.vars.prototype)|e }}">
        {# iterate over each existing tag and render its only field: name #}
        {% for subForm1 in form.subForm1 %}
            <li>{{ form_row(subForm1) }} </li>
             <ul class="collectionHolder" data-prototype="{{ form_widget(subForm2.vars.prototype)|e }}">
            {%for subForm2 in subForm1.subForm2 %}
                <li>{{ form_row(subForm2) }}</li>
            {% endfor %}

        {% endfor %}
    </ul>
{{ form_end(form) }}



<script>
var $collectionHolder;

// setup an "add a tag" linkd
var $addTagLink = $('<a href="#" class="add_tag_link">Add</a>');
var $newLinkLi = $('<li></li>').append($addTagLink);

jQuery(document).ready(function() {

    function addTagForm($collectionHolder, $newLinkLi) 
    { 
        // Get the data-prototype explained earlier
        var prototype = $collectionHolder.data('prototype');
        // get the new index
        var index = $collectionHolder.data('index');
        // Replace '__name__' in the prototype's HTML to
        // instead be a number based on how many items we have
        var newForm = prototype.replace(/__name__/g, index);

        // increase the index with one for the next item
        $collectionHolder.data('index', index + 1);

        // Display the form in the page in an li, before the "Add a tag" link li
        var $newFormLi = $('<li></li>').append(newForm);
        $newLinkLi.before($newFormLi);
     }


    $collectionHolder = $('.collectionHolder');

    $collectionHolder.append($newLinkLi);

    // count the current form inputs we have (e.g. 2), use that as the new
    // index when inserting a new item (e.g. 2)
    $collectionHolder.data('index', $collectionHolder.find(':input').length);

    $addTagLink.on('click', function(e) {
        e.preventDefault();
        addTagForm($collectionHolder, $newLinkLi);
    });
});
</script>
{% endblock content %}

Answer 1

Your problem is that the example javascript was not written to handle multiple collections at once.

I've written a seperate javascript file which I always include when handling these form collections:

// js/form.collection.js
function FormCollection(div_id)
{
    // keep reference to self in all child functions
    var self=this;

    self.construct = function () {
        // set some shortcuts
        self.div = $('#'+div_id);
        self.div.data('index', self.div.find(':input').length);

        // add delete link to existing children
        self.div.children().each(function() {
            self.addDeleteLink($(this));
        });

        // add click event to the Add new button
        self.div.next().on('click', function(e) {
            // prevent the link from creating a "#" on the URL
            e.preventDefault();

            // add a new tag form (see next code block)
            self.addNew();
        });
    };

    /**
     * onClick event handler -- adds a new input
     */
    self.addNew = function () {
        // Get the data-prototype explained earlier
        var prototype = self.div.data('prototype');

        // get the new index
        var index = self.div.data('index');

        // Replace '__name__' in the prototype's HTML to
        // instead be a number based on how many items we have
        var newForm = prototype.replace(/__name__/g, index);

        // increase the index with one for the next item
        self.div.data('index', index + 1);

        // Display the form in the page in an li, before the "Add a tag" link li
        self.div.append($(newForm));

        // add a delete link to the new form
        self.addDeleteLink( $(self.div.children(':last-child')[0]) );

        // not a very nice intergration.. but when creating stuff that has help icons, 
        // the popovers will not automatically be instantiated
        //initHelpPopovers();

        return $(newForm);
    };

    /**
     * add Delete icon after input
     * @param Element row
     */
    self.addDeleteLink = function (row) {
        var $removeFormA = $('<a href="#" class="btn btn-danger" tabindex="-1"><i class="entypo-trash"></i></a>');
        $(row).find('select').after($removeFormA);
        row.append($removeFormA);
        $removeFormA.on('click', function(e) {
            // prevent the link from creating a "#" on the URL
            e.preventDefault();

            // remove the li for the tag form
            row.remove();
        });
    };

    self.construct();
}

Within the desired template I then simply target the collections by id and add instantiate the FormCollection by id, such as:

{% extends '::base.html.twig' %}
{% block content %}

{{ form_start(form) }} 
    <h3>Tags</h3>
    <ul id="col-subform1" data-prototype="{{ form_widget(form.subForm1.vars.prototype)|e }}">
        {# iterate over each existing tag and render its only field: name #}
        {% for subForm1 in form.subForm1 %}
            <li>{{ form_row(subForm1) }} </li>
             <ul id="col-subform2" data-prototype="{{ form_widget(subForm2.vars.prototype)|e }}">
            {%for subForm2 in subForm1.subForm2 %}
                <li>{{ form_row(subForm2) }}</li>
            {% endfor %}

        {% endfor %}
    </ul>
{{ form_end(form) }}

<script type="text/javascript" src="/js/form.collection.js"></script>
<script type="text/javascript">
  new FormCollection('col-subform1');
  new FormCollection('col-subform2');
</script>