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Forms

Introduction

Form is the base class of all forms in a SilverStripe application. Forms in your application can be created either by instantiating the Form class itself, or by subclassing it.

Instantiating a form

Creating a form is a matter of defining a method to represent that form. This method should return a form object. The constructor takes the following arguments:

  • $controller: This must be the controller that contains the form.
  • $name: This must be the name of the method on that controller that is called to return the form. The first two fields allow the form object to be re-created after submission. It's vital that they are properly set - if you ever have problems with form action handler not working, check that these values are correct.
  • $fields: A [api:FieldList] containing [api:FormField] instances make up fields in the form.
  • $actions: A [api:FieldList] containing the [api:FormAction] objects - the buttons at the bottom.
  • $validator: An optional [api:Validator] for more information.

Example:

:::php
public function MyCustomForm() {
    $fields = new FieldList(
        new EmailField("Email"),
        new EncryptField("Password")
    );
    $actions = new FieldList(new FormAction("login", "Log in"));
    return new Form($this, "MyCustomForm", $fields, $actions);
}

Subclassing a form

It's the responsibility of your subclass' constructor to call

:::php
parent::__construct()

with the right parameters. You may choose to take $fields and $actions as arguments if you wish, but $controller and $name must be passed - their values depend on where the form is instantiated.

:::php
class MyForm extends Form {
    public function __construct($controller, $name) {
        $fields = new FieldList(
            new EmailField("Email"),
            new EncryptedField("Password")
        );
        $actions = new FieldList(new FormAction("login", "Log in"));

        parent::__construct($controller, $name, $fields, $actions);
    }
}

The real difference, however, is that you can then define your controller methods within the form class itself.

Form Field Types

There are many classes extending [api:FormField]. Some examples:

  • [api:TextField]
  • [api:EmailField]
  • [api:NumericField]
  • [api:DateField]
  • [api:CheckboxField]
  • [api:DropdownField]
  • [api:OptionsetField]
  • [api:CheckboxSetField]

Full overview at form-field-types

Using Form Fields

To get these fields automatically rendered into a form element, all you need to do is create a new instance of the class, and add it to the fieldlist of the form.

:::php
$form = new Form(
        $controller = $this,
        $name = "SignupForm",
        $fields = new FieldList(
            new TextField(
                $name = "FirstName", 
                $title = "First name"
            ),
            new TextField("Surname"),
            new EmailField("Email", "Email address"),
         ), 
        $actions = new FieldList(
            // List the action buttons here
            new FormAction("signup", "Sign up")
        ), 
        $requiredFields = new RequiredFields(
            // List the required fields here: "Email", "FirstName"
        )
);

You'll note some of the fields are optional.

Implementing the more complex fields requires extra arguments.

:::php
$form = new Form(
        $controller = $this,
        $name = "SignupForm",
        $fields = new FieldList(
            // List the your fields here
            new TextField(
                $name = "FirstName", 
                $title = "First name"
            ),
            new TextField("Surname"),
            new EmailField("Email", "Email address")
            new DropdownField(
                 $name = "Country",
                 $title = "Country (if outside nz)",
                 $source = Geoip::getCountryDropDown(),
                 $value = Geoip::visitor_country()
            )
        ), new FieldList(
            // List the action buttons here
            new FormAction("signup", "Sign up")

        ), new RequiredFields(
            // List the required fields here: "Email", "FirstName"
        )
);

Readonly

Readonly on a Form

:::php
$myForm->makeReadonly();

Readonly on a FieldList

:::php
$myFieldSet->makeReadonly();

Readonly on a FormField

:::php
$myReadonlyField = $myField->transform(new ReadonlyTransformation());
// shortcut
$myReadonlyField = $myField->performReadonlyTransformation();

Custom form templates

You can use a custom form template to render with, instead of Form.ss

It's recommended you only do this if you've got a lot of presentation text, graphics that surround the form fields. This is better than defining those as LiteralField objects, as it doesn't clutter the data layer with presentation junk.

First of all, you need to create your form on it's own class, that way you can define a custom template using a forTemplate() method on your Form class.

:::php
class MyForm extends Form {

   public function __construct($controller, $name) {
      $fields = new FieldList(
         new TextField('FirstName', 'First name'),
         new EmailField('Email', 'Email address')
      );

      $actions = new FieldList(
         new FormAction('submit', 'Submit')
      );

      parent::__construct($controller, $name, $fields, $actions);
   }

   public function forTemplate() {
      return $this->renderWith(array(
         $this->class,
         'Form'
      ));
   }

   public function submit($data, $form) {
      // do stuff here
   }

}

forTemplate() tells the [api:Form] class to render with a template of return value of $this->class, which in this case is MyForm, the name of the class. If the template doesn't exist, then it falls back to using Form.ss.

MyForm.ss should then be placed into your templates/Includes directory for your project. Here is an example of basic customisation:

:::ss
<form $FormAttributes>
   <% if Message %>
      <p id="{$FormName}_error" class="message $MessageType">$Message</p>
   <% else %>
      <p id="{$FormName}_error" class="message $MessageType" style="display: none"></p>
   <% end_if %>

   <fieldset>
      <div id="FirstName" class="field text">
         <label class="left" for="{$FormName}_FirstName">First name</label>
         $dataFieldByName(FirstName)
      </div>

      <div id="Email" class="field email">
         <label class="left" for="{$FormName}_Email">Email</label>
         $dataFieldByName(Email)
      </div>

      $dataFieldByName(SecurityID)
   </fieldset>

   <% if Actions %>
      <div class="Actions">
         <% loop Actions %>$Field<% end_loop %>
      </div>
   <% end_if %>
</form>

$dataFieldByName(FirstName) will return the form control contents of Field() for the particular field object, in this case TextField->Field() or EmailField->Field() which returns an <input> element with specific markup for the type of field. Pass in the name of the field as the first parameter, as done above, to render it into the template.

To find more methods, have a look at the [api:Form] class, as there is a lot of different methods of customising the form templates, for example, you could use <% loop Fields %> instead of specifying each field manually, as we've done above.

Custom form field templates

The easiest way to customize form fields is adding CSS classes and additional attributes.

:::php
$field = new TextField('MyText');
$field->addExtraClass('largeText');
$field->setAttribute('data-validation-regex', '[\d]*');

// Field() renders as:
// <input type="text" class="largeText" id="Form_Form_TextField" name="TextField" data-validation-regex="[\d]*">

Each form field is rendered into a form via the [FieldHolder()](api:FormField->FieldHolder()) method, which includes a container <div> as well as a <label> element (if applicable). You can also render each field without these structural elements through the [Field()](api:FormField->Field()) method. In order to influence the form rendering, overloading these two methods is a good start.

In addition, most form fields are rendered through SilverStripe templates, e.g. TextareaField is rendered via framework/templates/forms/TextareaField.ss. These templates can be overwritten globally by placing a template with the same name in your mysite directory, or set on a form field instance via [setTemplate()](api:FormField->setTemplate()) and [setFieldHolderTemplate()](api:FormField->setFieldHolderTemplate()).

Securing forms against Cross-Site Request Forgery (CSRF)

SilverStripe tries to protect users against Cross-Site Request Forgery (CSRF) by adding a hidden SecurityID parameter to each form. See secure-development for details.

Remove existing fields

If you want to remove certain fields from your subclass:

:::php
class MyCustomForm extends MyForm {
    public function __construct($controller, $name) {
        parent::__construct($controller, $name);

        // remove a normal field
        $this->fields->removeByName('MyFieldName');

        // remove a field from a tab
        $this->fields->removeFieldFromTab('TabName', 'MyFieldName');
    }
}

Working with tabs

Adds a new text field called FavouriteColour next to the Content field in the CMS

:::php
$fields->addFieldToTab('Root.Content', new TextField('FavouriteColour'), 'Content');

Related

API Documentation

  • [api:Form]
  • [api:FormField]
  • [api:FieldList]
  • [api:FormAction]
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