choice Field Type¶

A multi-purpose field used to allow the user to “choose” one or more options. It can be rendered as a select tag, radio buttons, or checkboxes.

To use this field, you must specify either the choice_list or choices option.

Rendered as	can be various tags (see below)
Options	choices choice_list empty_value expanded multiple preferred_choices
Overridden options	compound empty_data error_bubbling
Inherited options	by_reference data disabled error_mapping inherit_data label label_attr mapped read_only required
Parent type	form
Class	`ChoiceType`

Example Usage¶

The easiest way to use this field is to specify the choices directly via the choices option. The key of the array becomes the value that’s actually set on your underlying object (e.g. m), while the value is what the user sees on the form (e.g. Male).

$builder->add('gender', 'choice', array(
    'choices'   => array('m' => 'Male', 'f' => 'Female'),
    'required'  => false,
));

By setting multiple to true, you can allow the user to choose multiple values. The widget will be rendered as a multiple select tag or a series of checkboxes depending on the expanded option:

$builder->add('availability', 'choice', array(
    'choices'   => array(
        'morning'   => 'Morning',
        'afternoon' => 'Afternoon',
        'evening'   => 'Evening',
    ),
    'multiple'  => true,
));

You can also use the choice_list option, which takes an object that can specify the choices for your widget.

Select Tag, Checkboxes or Radio Buttons¶

This field may be rendered as one of several different HTML fields, depending on the expanded and multiple options:

Element Type	Expanded	Multiple
select tag	`false`	`false`
select tag (with `multiple` attribute)	`false`	`true`
radio buttons	`true`	`false`
checkboxes	`true`	`true`

Field Options¶

choices¶

type: array default: array()

This is the most basic way to specify the choices that should be used by this field. The choices option is an array, where the array key is the item value and the array value is the item’s label:

$builder->add('gender', 'choice', array(
    'choices' => array('m' => 'Male', 'f' => 'Female')
));

小技巧

When the values to choose from are not integers or strings (but e.g. floats or booleans), you should use the choice_list option instead. With this option you are able to keep the original data format which is important to ensure that the user input is validated properly and useless database updates caused by a data type mismatch are avoided.

choice_list¶

type: ChoiceListInterface

This is one way of specifying the options to be used for this field. The choice_list option must be an instance of the ChoiceListInterface. For more advanced cases, a custom class that implements the interface can be created to supply the choices.

With this option you can also allow float values to be selected as data.

use Symfony\Component\Form\Extension\Core\ChoiceList\ChoiceList;

// ...
$builder->add('status', 'choice', array(
  'choice_list' => new ChoiceList(array(1, 0.5), array('Full', 'Half'))
));

empty_value¶

2.3 新版功能: Since Symfony 2.3, empty values are also supported if the expanded option is set to true.

type: string or Boolean

This option determines whether or not a special “empty” option (e.g. “Choose an option”) will appear at the top of a select widget. This option only applies if the multiple option is set to false.

Add an empty value with “Choose an option” as the text:

$builder->add('states', 'choice', array(
    'empty_value' => 'Choose an option',
));

Guarantee that no “empty” value option is displayed:

$builder->add('states', 'choice', array(
    'empty_value' => false,
));

If you leave the empty_value option unset, then a blank (with no text) option will automatically be added if and only if the required option is false:

// a blank (with no text) option will be added
$builder->add('states', 'choice', array(
    'required' => false,
));

expanded¶

type: Boolean default: false

If set to true, radio buttons or checkboxes will be rendered (depending on the multiple value). If false, a select element will be rendered.

multiple¶

type: Boolean default: false

If true, the user will be able to select multiple options (as opposed to choosing just one option). Depending on the value of the expanded option, this will render either a select tag or checkboxes if true and a select tag or radio buttons if false. The returned value will be an array.

preferred_choices¶

type: array default: array()

If this option is specified, then a sub-set of all of the options will be moved to the top of the select menu. The following would move the “Baz” option to the top, with a visual separator between it and the rest of the options:

$builder->add('foo_choices', 'choice', array(
    'choices' => array('foo' => 'Foo', 'bar' => 'Bar', 'baz' => 'Baz'),
    'preferred_choices' => array('baz'),
));

Note that preferred choices are only meaningful when rendering as a select element (i.e. expanded is false). The preferred choices and normal choices are separated visually by a set of dotted lines (i.e. -------------------). This can be customized when rendering the field:

Twig

{{ form_widget(form.foo_choices, { 'separator': '=====' }) }}

PHP

<?php echo $view['form']->widget($form['foo_choices'], array('separator' => '=====')) ?>

Overridden Options¶

compound¶

type: boolean default: same value as expanded option

This option specifies if a form is compound. The value is by default overridden by the value of the expanded option.

empty_data¶

type: mixed

The actual default value of this option depends on other field options:

If multiple is false and expanded is false, then '' (empty string);
Otherwise array() (empty array).

This option determines what value the field will return when the submitted value is empty.

But you can customize this to your needs. For example, if you want the gender choice field to be explicitly set to null when no value is selected, you can do it like this:

$builder->add('gender', 'choice', array(
    'choices' => array(
        'm' => 'Male',
        'f' => 'Female'
    ),
    'required'    => false,
    'empty_value' => 'Choose your gender',
    'empty_data'  => null
));

注解

If you want to set the empty_data option for your entire form class, see the cookbook article How to Configure empty Data for a Form Class.

error_bubbling¶

type: boolean default: false

Set that error on this field must be attached to the field instead of the parent field (the form in most cases).

Inherited Options¶

These options inherit from the form type:

by_reference¶

type: Boolean default: true

In most cases, if you have a name field, then you expect setName() to be called on the underlying object. In some cases, however, setName() may not be called. Setting by_reference ensures that the setter is called in all cases.

To explain this further, here’s a simple example:

$builder = $this->createFormBuilder($article);
$builder
    ->add('title', 'text')
    ->add(
        $builder->create('author', 'form', array('by_reference' => ?))
            ->add('name', 'text')
            ->add('email', 'email')
    )

If by_reference is true, the following takes place behind the scenes when you call submit() (or handleRequest()) on the form:

$article->setTitle('...');
$article->getAuthor()->setName('...');
$article->getAuthor()->setEmail('...');

Notice that setAuthor() is not called. The author is modified by reference.

If you set by_reference to false, submitting looks like this:

$article->setTitle('...');
$author = $article->getAuthor();
$author->setName('...');
$author->setEmail('...');
$article->setAuthor($author);

So, all that by_reference=false really does is force the framework to call the setter on the parent object.

Similarly, if you’re using the collection form type where your underlying collection data is an object (like with Doctrine’s ArrayCollection), then by_reference must be set to false if you need the adder and remover (e.g. addAuthor() and removeAuthor()) to be called.

data¶

type: mixed default: Defaults to field of the underlying object (if there is one)

When you create a form, each field initially displays the value of the corresponding property of the form’s domain object (if an object is bound to the form). If you want to override the initial value for the form or just an individual field, you can set it in the data option:

$builder->add('token', 'hidden', array(
    'data' => 'abcdef',
));

注解

The default values for form fields are taken directly from the underlying data structure (e.g. an entity or an array). The data option overrides this default value.

disabled¶

2.1 新版功能: The disabled option was introduced in Symfony 2.1.

type: boolean default: false

If you don’t want a user to modify the value of a field, you can set the disabled option to true. Any submitted value will be ignored.

error_mapping¶

2.1 新版功能: The error_mapping option was introduced in Symfony 2.1.

type: array default: empty

This option allows you to modify the target of a validation error.

Imagine you have a custom method named matchingCityAndZipCode that validates whether the city and zip code match. Unfortunately, there is no “matchingCityAndZipCode” field in your form, so all that Symfony can do is display the error on top of the form.

With customized error mapping, you can do better: map the error to the city field so that it displays above it:

public function setDefaultOptions(OptionsResolverInterface $resolver)
{
    $resolver->setDefaults(array(
        'error_mapping' => array(
            'matchingCityAndZipCode' => 'city',
        ),
    ));
}

Here are the rules for the left and the right side of the mapping:

The left side contains property paths;
If the violation is generated on a property or method of a class, its path is simply propertyName;
If the violation is generated on an entry of an array or ArrayAccess object, the property path is [indexName];
You can construct nested property paths by concatenating them, separating properties by dots. For example: addresses[work].matchingCityAndZipCode;
The left side of the error mapping also accepts a dot ., which refers to the field itself. That means that any error added to the field is added to the given nested field instead;
The right side contains simply the names of fields in the form.

inherit_data¶

2.3 新版功能: The inherit_data option was introduced in Symfony 2.3. Before, it was known as virtual.

type: boolean default: false

This option determines if the form will inherit data from its parent form. This can be useful if you have a set of fields that are duplicated across multiple forms. See How to Reduce Code Duplication with “inherit_data”.

label¶

type: string default: The label is “guessed” from the field name

Sets the label that will be used when rendering the field. Setting to false will suppress the label. The label can also be directly set inside the template:

Twig

{{ form_label(form.name, 'Your name') }}

PHP

echo $view['form']->label(
    $form['name'],
    'Your name'
);

label_attr¶

type: array default: array()

Sets the HTML attributes for the <label> element, which will be used when rendering the label for the field. It’s an associative array with HTML attribute as a key. This attributes can also be directly set inside the template:

Twig

{{ form_label(form.name, 'Your name', {'label_attr': {'class': 'CUSTOM_LABEL_CLASS'}}) }}

PHP

echo $view['form']->label(
    $form['name'],
    'Your name',
    array('label_attr' => array('class' => 'CUSTOM_LABEL_CLASS'))
);

mapped¶

type: boolean default: true

If you wish the field to be ignored when reading or writing to the object, you can set the mapped option to false.

read_only¶

type: Boolean default: false

If this option is true, the field will be rendered with the readonly attribute so that the field is not editable.

required¶

type: Boolean default: true

If true, an HTML5 required attribute will be rendered. The corresponding label will also render with a required class.

This is superficial and independent from validation. At best, if you let Symfony guess your field type, then the value of this option will be guessed from your validation information.

注解

The required option also affects how empty data for each field is handled. For more details, see the empty_data option.

Field Variables¶

Variable	Type	Usage
multiple	`Boolean`	The value of the multiple option.
expanded	`Boolean`	The value of the expanded option.
preferred_choices	`array`	A nested array containing the `ChoiceView` objects of choices which should be presented to the user with priority.
choices	`array`	A nested array containing the `ChoiceView` objects of the remaining choices.
separator	`string`	The separator to use between choice groups.
empty_value	`mixed`	The empty value if not already in the list, otherwise `null`.
is_selected	`callable`	A callable which takes a `ChoiceView` and the selected value(s) and returns whether the choice is in the selected value(s).
empty_value_in_choices	`Boolean`	Whether the empty value is in the choice list.

小技巧

It’s significantly faster to use the selectedchoice(selected_value) test instead when using Twig.