Question

There was a method with CCK in Drupal 6 to attach a CCK field in our custom form, like:

$field = content_fields('field_name');  // field_name is cck field
(text_field,text_Area,image_field anything.)
$form['#field_info'][$name] = $field;
$form += content_field_form($form, $form_state, $field);

How can I achieve the same functionality in Drupal 7? I had a form and I want to use the field that I created for a content type. I went through all the files of field.module but couldn’t find anything. There are functions in it like _attach_field, field_info_Field and field_info_instance, but they can’t be rendered as a form field.

Answer 1

I like your solution of adding the entire form and unsetting. I am attacking it from another angle– create a throw-away temporary form and copy in only the field(s) you wish to preserve. Here’s what I posted at http://api.drupal.org/api/drupal/modules%21field%21field.attach.inc/function/field_attach_form/7#comment-45908:

To add a single field off an arbitrary entity bundle (in this case, an autocomplete nodereference textfield) onto another form, create the form as a temporary form and formstate, and copy in to place that field definition. In my case, I’m working on a Commerce checkout form alter:

function example_form_commerce_checkout_form_checkout_alter(&$form, &$form_state, $form_id) {
  $tmpform = array();
  $tmpform_state = array();
  $tmpnode = new stdClass();
  $tmpnode->type = 'card';
  // Create the temporary form/state by reference
  field_attach_form('node', $tmpnode, $tmpform, $tmpform_state);
  // Create a new fieldset on the Commerce checkout form
  $form['cart_contents']['org_ref_wrap'] = array(
    '#type' => 'fieldset',
    '#title' => t('Support Organization'),
  );
  // Place a copy of the new form field within the new fieldset
  $form['cart_contents']['org_ref_wrap'][] = $tmpform['field_card_organization'];
  // Copy over the $form_state field element as well to avoid Undefined index notices
  $form_state['field']['field_card_organization'] = $tmpform_state['field']['field_card_organization'];

  ..

The advantage to either solution likely depends on the complexity of the “source” form (too complex means a lot of unsets with the form-insert method) and whether the source form will ever receive new fields over time (new fields will show up on your “destination” form in the form-insert method).

Thanks for sharing your solution!