Cannot deal with multiple iterations of same form on one page

Question

I am designing a site that has a variety of points in which I need to render "workflow" buttons that are used to send actions to an external application.

I used the form API to generate these buttons, and am using the #submit => option on my buttons to direct specific button types to custom functions. I am also using hidden fields to house data that I use to facilitate the action.

The problem I am having is that these buttons can and should show up multiple times per page, for different aspects of the application, and whenever I click one of the buttons Drupal attempts to submit all of the forms.

I guess what i am asking is, how can I have multiple instances of the exact same form on screen at any given time, and know with certainty that the submit buttons are only going to trigger actions for the specific instance of the form they belong to?

thanks in advance!!

Edit

So here is the crux of the problem - it appears that the getFormId needs to return a unique value, but I cannot figure out how to pass unique values into it.

Answer 1

Yes, each form must have a unique form ID. See https://www.drupal.org/node/766146 and the comments there.

You need to find something that uniquely identifies each form and put that in the form ID.
As commented there, that can be a bit tricky as getFormId() is called very early, so you need to instantiate the form object yourself and pass it to the form builder.

See FormBuilder::getFormId() for what happens when you pass in a string, it is passed to $this->classResolver->getInstanceFromDefinition($form_arg);, that creates the object and uses the create() method if available, you can use that or just do it yourself with a new Object(), then pass that to getForm() instead.

Answer 2

You could also add something like this to your form class

 /**
  * Keep track of how many times the form
  * is placed on a page.
  *
  * @var int
  */
protected static $instanceId;

/**
 * {@inheritdoc}
 */
public function getFormId() {
  if (empty(self::$instanceId)) {
    self::$instanceId = 1;
  }
  else {
    self::$instanceId++;
  }

  return 'my_form_id_' . self::$instanceId;
}