silverstripe-framework/docs/en/02_Developer_Guides/03_Forms/How_Tos/01_Encapsulate_Forms.md

title: How to Encapsulate Forms

# How to Encapsulate Forms

Form definitions can often get long, complex and often end up cluttering up a `Controller` definition. We may also want
to reuse the `Form` across multiple `Controller` classes rather than just one. A nice way to encapsulate the logic and 
code for a `Form` is to create it as a subclass to `Form`. Let's look at a example of a `Form` which is on our 
`Controller` but would be better written as a subclass.
	
**mysite/code/Page.php**

	:::php
	<?php

	class Page_Controller extends ContentController {
		
		public function SearchForm() {
			$fields = new FieldList(
				HeaderField::create('Header', 'Step 1. Basics'),
				OptionsetField::create('Type', '', array(
					'foo' => 'Search Foo',
					'bar' => 'Search Bar',
					'baz' => 'Search Baz'
				)),

				CompositeField::create(
					HeaderField::create('Header2', 'Step 2. Advanced '),
					CheckboxSetField::create('Foo', 'Select Option', array(
						'qux' => 'Search Qux'
					)),

					CheckboxSetField::create('Category', 'Category', array(
						'Foo' => 'Foo',
						'Bar' => 'Bar'
					)),

					NumericField::create('Minimum', 'Minimum'),
					NumericField::create('Maximum', 'Maximum')
				)
			);
			
			$actions = new FieldList(
				FormAction::create('doSearchForm', 'Search')
			);
			
			$required = new RequiredFields(array(
				'Type'
			));

			$form = new Form($this, 'SearchForm', $fields, $actions, $required);
			$form->setFormMethod('GET');
			
			$form->addExtraClass('no-action-styles');
			$form->disableSecurityToken();
			$form->loadDataFrom($_REQUEST);
		
			return $form;
		}

		..
	}

Now that is a bit of code to include on our controller and generally makes the file look much more complex than it 
should be. Good practice would be to move this to a subclass and create a new instance for your particular controller.

**mysite/code/forms/SearchForm.php**

	:::php
	<?php

	class SearchForm extends Form {

		/**
		 * Our constructor only requires the controller and the name of the form
		 * method. We'll create the fields and actions in here.
		 *
		 */
		public function __construct($controller, $name) {
			$fields = new FieldList(
				HeaderField::create('Header', 'Step 1. Basics'),
				OptionsetField::create('Type', '', array(
					'foo' => 'Search Foo',
					'bar' => 'Search Bar',
					'baz' => 'Search Baz'
				)),

				CompositeField::create(
					HeaderField::create('Header2', 'Step 2. Advanced '),
					CheckboxSetField::create('Foo', 'Select Option', array(
						'qux' => 'Search Qux'
					)),

					CheckboxSetField::create('Category', 'Category', array(
						'Foo' => 'Foo',
						'Bar' => 'Bar'
					)),

					NumericField::create('Minimum', 'Minimum'),
					NumericField::create('Maximum', 'Maximum')
				)
			);
			
			$actions = new FieldList(
				FormAction::create('doSearchForm', 'Search')
			);
			
			$required = new RequiredFields(array(
				'Type'
			));

			// now we create the actual form with our fields and actions defined
			// within this class
			parent::__construct($controller, $name, $fields, $actions, $required);

			// any modifications we need to make to the form.
			$this->setFormMethod('GET');
		
			$this->addExtraClass('no-action-styles');
			$this->disableSecurityToken();
			$this->loadDataFrom($_REQUEST);
		}
	}

Our controller will now just have to create a new instance of this form object. Keeping the file light and easy to read.

**mysite/code/Page.php**

	:::php
	<?php

	class Page_Controller extends ContentController {
		
		private static $allowed_actions = array(
			'SearchForm',
		);
		
		public function SearchForm() {
			return new SearchForm($this, 'SearchForm');
		}
	}

Form actions can also be defined within your `Form` subclass to keep the entire form logic encapsulated.

## Related Documentation

* [Introduction to Forms](../introduction)

## API Documentation

* [api:Form]