1 tabledrag_example_parent_form.inc tabledrag_example_parent_form($form_state)

Build the parent-child example form.

Tabledrag will take care of updating the parent_id relationship on each row of our table when we drag items around, but we need to build out the initial tree structure ourselves. This means ordering our items such that children items come directly after their parent items, and all items are sorted by weight relative to their siblings.

To keep this from cluttering the actual tabledrag code, we have moved this to a dedicated function.

Return value

array: A form array set for theming by theme_tabledrag_example_parent_form()

Related topics


modules/examples/tabledrag_example/tabledrag_example_parent_form.inc, line 24
Example demonstrating a parent/child tabledrag form


function tabledrag_example_parent_form($form_state) {
  // Identify that the elements in 'example_items' are a collection, to
  // prevent Form API from flattening the array when submitted.
  $form['example_items']['#tree'] = TRUE;

  // Fetch the example data from the database, ordered by parent/child/weight.
  $result = tabledrag_example_parent_get_data();

  // Iterate through each database result.
  foreach ($result as $item) {

    // Create a form entry for this item.
    // Each entry will be an array using the the unique id for that item as
    // the array key, and an array of table row data as the value.
    $form['example_items'][$item->id] = array(

      // We'll use a form element of type '#markup' to display the item name.
      'name' => array(
        '#markup' => $item->name,

      // We'll use a form element of type '#textfield' to display the item
      // description, to demonstrate that form elements can be included in the
      // table. We limit the input to 255 characters, which is the limit we
      // set on the database field.
      'description' => array(
        '#type' => 'textfield',
        '#default_value' => $item->description,
        '#size' => 20,
        '#maxlength' => 255,

      // For parent/child relationships, we also need to add form items to
      // store the current item's unique id and parent item's unique id.
      // We would normally use a hidden element for this, but for this example
      // we'll use a disabled textfield element called 'id' so that we can
      // display the current item's id in the table.
      // Because tabledrag modifies the #value of this element, we use
      // '#default_value' instead of '#value' when defining a hidden element.
      // Also, because tabledrag modifies '#value', we cannot use a markup
      // element, which does not support the '#value' property. (Markup
      // elements use the '#markup' property instead.)
      'id' => array(
        // '#type' => 'hidden',
        // '#default_value' => $item->id,
        '#type' => 'textfield',
        '#size' => 3,
        '#default_value' => $item->id,
        '#disabled' => TRUE,

      // The same information holds true for the parent id field as for the
      // item id field, described above.
      'pid' => array(
        // '#type' => 'hidden',
        // '#default_value' => $item->pid,
        '#type' => 'textfield',
        '#size' => 3,
        '#default_value' => $item->pid,

      // The 'weight' field will be manipulated as we move the items around in
      // the table using the tabledrag activity.  We use the 'weight' element
      // defined in Backdrop's Form API.
      'weight' => array(
        '#type' => 'weight',
        '#title' => t('Weight'),
        '#default_value' => $item->weight,
        '#delta' => 10,
        '#title_display' => 'invisible',

      // We'll use a hidden form element to pass the current 'depth' of each
      // item within our parent/child tree structure to the theme function.
      // This will be used to calculate the initial amount of indentation to
      // add before displaying any child item rows.
      'depth' => array(
        '#type' => 'hidden',
        '#value' => $item->depth,

  // Now we add our submit button, for submitting the form results.
  // The 'actions' wrapper used here isn't strictly necessary for tabledrag,
  // but is included as a Form API recommended practice.
  $form['actions'] = array('#type' => 'actions');
  $form['actions']['submit'] = array('#type' => 'submit', '#value' => t('Save Changes'));
  return $form;