Form generation in Drupal 7

Same name and namespace in other branches

1. 8 core/core.api.php \form_api
2. 6 includes/form.inc \form_api
3. 9 core/core.api.php \form_api

Functions to enable the processing and display of HTML forms.

Drupal uses these functions to achieve consistency in its form processing and presentation, while simplifying code and reducing the amount of HTML that must be explicitly generated by modules.

The primary function used with forms is drupal_get_form(), which is used for forms presented interactively to a user. Forms can also be built and submitted programmatically without any user input using the drupal_form_submit() function.

drupal_get_form() handles retrieving, processing, and displaying a rendered HTML form for modules automatically.

Here is an example of how to use drupal_get_form() and a form builder function:

$form = drupal_get_form('my_module_example_form');
...
function my_module_example_form($form, &$form_state) {
  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Submit'),
  );
  return $form;
}
function my_module_example_form_validate($form, &$form_state) {
  // Validation logic.
}
function my_module_example_form_submit($form, &$form_state) {
  // Submission logic.
}

Or with any number of additional arguments:

$extra = "extra";
$form = drupal_get_form('my_module_example_form', $extra);
...
function my_module_example_form($form, &$form_state, $extra) {
  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => $extra,
  );
  return $form;
}

The $form argument to form-related functions is a structured array containing the elements and properties of the form. For information on the array components and format, and more detailed explanations of the Form API workflow, see the Form API reference and the Form API documentation section. In addition, there is a set of Form API tutorials in the Form Example Tutorial which provide basics all the way up through multistep forms.

In the form builder, validation, submission, and other form functions, $form_state is the primary influence on the processing of the form and is passed by reference to most functions, so they use it to communicate with the form system and each other.

See drupal_build_form() for documentation of $form_state keys.

File

includes/form.inc, line 25

Functions for form and batch generation and processing.

Functions