Add hook alter to override field_multiple_value_form()

An example is to have a multivalue widget where the user is not allowed to sort the data, and you need to remove the 'Order' column and the drag&drop js.

An alternative method is the following:
- create a MYMODULE_field_multiple_value_form($variables) function in MYMODULE.theme.inc , which overrides the original function. You can copy and modify the original code of theme_field_multiple_value_form;
- add the following in MYMODULE.module:

/**
 * Implements hook_theme().
 */
function MYMODULE_theme ($existing, $type, $theme, $path) {
  $base = array(
    'file' => 'MYMODULE.theme.inc',
    'path' => "$path",
  );
  $themes = array(
    'field_multiple_value_form' => $base + array('render element' => 'element'),
  );
  return $themes;
}

I'm using Drupal 7.17. Discovered a module using this:

function hook_preprocess_field_multiple_value_form(&$variables)

So, I used it myself in one of my own custom modules and it's working well. Maybe that's not -exactly- the same thing as this, but perhaps useful to mention. I didn't find any documentation on implementing this as a hook.

Same here, didn't find any information related to hook_preprocess_field_multiple_value_form. Does this feature do something like Field Collection module where we can add multiple field elements on choosing multiple values of different widget type ?

This is a simple enhancement, I'm using this to add another control button for references thumbnail.

It's been a while but I thought I'd make a note, since this issue is high in search results and it seems like this is still something a lot of people struggle with.

hook_preprocess_field_multiple_value_form(&$variables) is not a specific undocumented hook but is an implementation of hook_preprocess_HOOK(). The theme being preprocessed is theme_field_multiple_value_form().

The patch in #5 looks good and simple. However, I kind of feel like it would make more sense to refactor the logic that calls field_multiple_value_form() so that it could be modified using existing known hooks like hook_form_alter() or maybe even the widget alter hooks. Adding a specific hook just for this form element seems unnecessary.

change name of hook_field_alter.

field_multiple_value_form() is a huge form. Sometimes it would be useful to be able replace entire form as well. This patch is required for Multiple Value Widget module (7.x-2.x branch).

Ha Ha I came up with a much simpler option so I could set one image field as many in one content type and limit it to one on my other content types:

function mymodule_form_alter(&$form, &$form_state, $form_id) {
  if(isset($form['#node_edit_form'])){
    if($form_id=='mycontenttype1_node_form'){
      unset($form['field_image']['und'][1]);
    }
  }
}

It's possible I missed an IRC conversation, but it seems there are a couple of different patches that take entirely different approaches and no real feedback about any of them, so I'm not 100% sure what got reviewed and tested.

I'd say that patch #5 is probably the way to go, if anything is going to be committed (and I'm guilty of not submitting any patch alternatives). #7 is an interesting idea but I don't think using variable_set() to control what function builds a form fits expectations created by other Form API patterns, which generally depend on using alter hooks to modify or replace default form structures.

Please review this patch.

Hi!

I've tested it under simplytest.me with Drupal 7.x. It seems working well so I changed its status to RTBC.

It passed simpletest in my environment so I'm not sure what that is about.

Tweaking the API documentation slightly and re-testing. Let's see what happens this time!

Last re-test passed. Failures seem random and not related. Not switching it directly to RCTB just because I made a (minor) change.

Pretty sure this would be relevant for Drupal 8 too, right? (I don't see an equivalent hook or way to alter the whole multivalued form structure there either.)

Quick review in the meantime:

+ *   - "form": The form structure where widgets are being attached to. This
+ *     might be a full form structure, or a sub-element of a larger form.
+ *   - "field": The field structure.
+ *   - "instance": The field instance structure.
+ *   - "langcode": The language associated with $items.
+ *   - "items": Array of default values for this field.

Don't think these should have quotes around them?

+  if ($context['instance']['field_name'] == 'body') {
+    // @todo Needs function body.
+  }

Would be nice to fill that in :)

I didn't find this when I search for it back in 2016.... so I made an issue #2822460: No hook to edit Field Widget wrappers created by WidgetBase::formMultipleElements, with a functional patch however without tests. But I got busy and didn't push it/write tests and *another* issue was created #2940201: hook_field_widget_form_alter() can no longer affect the whole widget for multi-value fields with effectively identical functionality + tests. That one got into 8.5.x. So despite this issue being the oldest of the three, closing it as duplicate.