.. index:: single: Forms; Fields; collection
This field type is used to render a "collection" of some field or form. In
the easiest sense, it could be an array of text fields that populate
an array emails field. In more complex examples, you can embed entire
forms, which is useful when creating forms that expose one-to-many relationships
(e.g. a product from where you can manage many related product photos).
| Rendered as | depends on the type option |
| Options | |
| Inherited options | |
| Parent type | :doc:`form </reference/forms/types/form>` |
| Class | :class:`Symfony\\Component\\Form\\Extension\\Core\\Type\\CollectionType` |
Note
If you are working with a collection of Doctrine entities, pay special attention to the allow_add, allow_delete and `by_reference`_ options. You can also see a complete example in the cookbook article :doc:`/cookbook/form/form_collections`.
This type is used when you want to manage a collection of similar items in
a form. For example, suppose you have an emails field that corresponds
to an array of email addresses. In the form, you want to expose each email
address as its own input text box:
$builder->add('emails', 'collection', array(
// each item in the array will be an "email" field
'type' => 'email',
// these options are passed to each "email" type
'options' => array(
'required' => false,
'attr' => array('class' => 'email-box')
),
));
The simplest way to render this is all at once:
.. configuration-block::
.. code-block:: jinja
{{ form_row(form.emails) }}
.. code-block:: php
<?php echo $view['form']->row($form['emails']) ?>
A much more flexible method would look like this:
.. configuration-block::
.. code-block:: html+jinja
{{ form_label(form.emails) }}
{{ form_errors(form.emails) }}
<ul>
{% for emailField in form.emails %}
<li>
{{ form_errors(emailField) }}
{{ form_widget(emailField) }}
</li>
{% endfor %}
</ul>
.. code-block:: html+php
<?php echo $view['form']->label($form['emails']) ?>
<?php echo $view['form']->errors($form['emails']) ?>
<ul>
<?php foreach ($form['emails'] as $emailField): ?>
<li>
<?php echo $view['form']->errors($emailField) ?>
<?php echo $view['form']->widget($emailField) ?>
</li>
<?php endforeach; ?>
</ul>
In both cases, no input fields would render unless your emails data array
already contained some emails.
In this simple example, it's still impossible to add new addresses or remove
existing addresses. Adding new addresses is possible by using the allow_add
option (and optionally the prototype option) (see example below). Removing
emails from the emails array is possible with the allow_delete option.
If allow_add is set to true, then if any unrecognized items are submitted,
they'll be added seamlessly to the array of items. This is great in theory,
but takes a little bit more effort in practice to get the client-side JavaScript
correct.
Following along with the previous example, suppose you start with two
emails in the emails data array. In that case, two input fields will
be rendered that will look something like this (depending on the name of
your form):
<input type="email" id="form_emails_0" name="form[emails][0]" value="foo@foo.com" />
<input type="email" id="form_emails_1" name="form[emails][1]" value="bar@bar.com" />To allow your user to add another email, just set allow_add to true
and - via JavaScript - render another field with the name form[emails][2]
(and so on for more and more fields).
To help make this easier, setting the prototype option to true allows
you to render a "template" field, which you can then use in your JavaScript
to help you dynamically create these new fields. A rendered prototype field
will look like this:
<input type="email" id="form_emails___name__" name="form[emails][__name__]" value="" />By replacing __name__ with some unique value (e.g. 2),
you can build and insert new HTML fields into your form.
Using jQuery, a simple example might look like this. If you're rendering
your collection fields all at once (e.g. form_row(form.emails)), then
things are even easier because the data-prototype attribute is rendered
automatically for you (with a slight difference - see note below) and all
you need is the JavaScript:
.. configuration-block::
.. code-block:: html+jinja
{{ form_start(form) }}
{# ... #}
{# store the prototype on the data-prototype attribute #}
<ul id="email-fields-list" data-prototype="{{ form_widget(form.emails.vars.prototype)|e }}">
{% for emailField in form.emails %}
<li>
{{ form_errors(emailField) }}
{{ form_widget(emailField) }}
</li>
{% endfor %}
</ul>
<a href="#" id="add-another-email">Add another email</a>
{# ... #}
{{ form_end(form) }}
<script type="text/javascript">
// keep track of how many email fields have been rendered
var emailCount = '{{ form.emails|length }}';
jQuery(document).ready(function() {
jQuery('#add-another-email').click(function() {
var emailList = jQuery('#email-fields-list');
// grab the prototype template
var newWidget = emailList.attr('data-prototype');
// replace the "__name__" used in the id and name of the prototype
// with a number that's unique to your emails
// end name attribute looks like name="contact[emails][2]"
newWidget = newWidget.replace(/__name__/g, emailCount);
emailCount++;
// create a new list element and add it to the list
var newLi = jQuery('<li></li>').html(newWidget);
newLi.appendTo(jQuery('#email-fields-list'));
return false;
});
})
</script>
Tip
If you're rendering the entire collection at once, then the prototype
is automatically available on the data-prototype attribute of the
element (e.g. div or table) that surrounds your collection. The
only difference is that the entire "form row" is rendered for you, meaning
you wouldn't have to wrap it in any container element as it was done
above.
type: string or :class:`Symfony\\Component\\Form\\FormTypeInterface` required
This is the field type for each item in this collection (e.g. text, choice,
etc). For example, if you have an array of email addresses, you'd use the
:doc:`email </reference/forms/types/email>` type. If you want to embed
a collection of some other form, create a new instance of your form type
and pass it as this option.
type: array default: array()
This is the array that's passed to the form type specified in the type
option. For example, if you used the :doc:`choice </reference/forms/types/choice>`
type as your type option (e.g. for a collection of drop-down menus), then
you'd need to at least pass the choices option to the underlying type:
$builder->add('favorite_cities', 'collection', array(
'type' => 'choice',
'options' => array(
'choices' => array(
'nashville' => 'Nashville',
'paris' => 'Paris',
'berlin' => 'Berlin',
'london' => 'London',
),
),
));
type: Boolean default: false
If set to true, then if unrecognized items are submitted to the collection,
they will be added as new items. The ending array will contain the existing
items as well as the new item that was in the submitted data. See the above
example for more details.
The prototype option can be used to help render a prototype item that can be used - with JavaScript - to create new form items dynamically on the client side. For more information, see the above example and :ref:`cookbook-form-collections-new-prototype`.
Caution!
If you're embedding entire other forms to reflect a one-to-many database relationship, you may need to manually ensure that the foreign key of these new objects is set correctly. If you're using Doctrine, this won't happen automatically. See the above link for more details.
type: Boolean default: false
If set to true, then if an existing item is not contained in the submitted
data, it will be correctly absent from the final array of items. This means
that you can implement a "delete" button via JavaScript which simply removes
a form element from the DOM. When the user submits the form, its absence
from the submitted data will mean that it's removed from the final array.
For more information, see :ref:`cookbook-form-collections-remove`.
Caution!
Be careful when using this option when you're embedding a collection of objects. In this case, if any embedded forms are removed, they will correctly be missing from the final array of objects. However, depending on your application logic, when one of those objects is removed, you may want to delete it or at least remove its foreign key reference to the main object. None of this is handled automatically. For more information, see :ref:`cookbook-form-collections-remove`.
type: Boolean default: true
This option is useful when using the allow_add option. If true (and
if allow_add is also true), a special "prototype" attribute will be
available so that you can render a "template" example on your page of what
a new element should look like. The name attribute given to this element
is __name__. This allows you to add a "add another" button via JavaScript
which reads the prototype, replaces __name__ with some unique name or
number, and render it inside your form. When submitted, it will be added
to your underlying array due to the allow_add option.
The prototype field can be rendered via the prototype variable in the
collection field:
.. configuration-block::
.. code-block:: jinja
{{ form_row(form.emails.vars.prototype) }}
.. code-block:: php
<?php echo $view['form']->row($form['emails']->vars['prototype']) ?>
Note that all you really need is the "widget", but depending on how you're rendering your form, having the entire "form row" may be easier for you.
Tip
If you're rendering the entire collection field at once, then the prototype
form row is automatically available on the data-prototype attribute
of the element (e.g. div or table) that surrounds your collection.
For details on how to actually use this option, see the above example as well as :ref:`cookbook-form-collections-new-prototype`.
type: String default: __name__
If you have several collections in your form, or worse, nested collections you may want to change the placeholder so that unrelated placeholders are not replaced with the same value.
These options inherit from the :doc:`form </reference/forms/types/form>` type. Not all options are listed here - only the most applicable to this type:
type: Boolean default: true
| Variable | Type | Usage |
|---|---|---|
| allow_add | Boolean |
The value of the allow_add option. |
| allow_delete | Boolean |
The value of the allow_delete option. |