Question

I’m trying to create an element that contains a form so it can be used throughout my site. The model used by the form has a belongsTo relationship with another table. In the baked add view I get a nice HTML select element with all the values from the related table. Think of blog posts and selecting from a list of categories.

How can I create an element that works the same way?

I have tried getting the data into the element using

$someVar = $this->requestAction('posts/add');

and in the PostsController

...
$categories = $this->Post->Category->find('list');
if (isset($this->params['requested'])) {
   return compact('categories');
} else {
   $this->set(compact('categories'));
}

but I don’t know where this data needs to go so that it is picked up by

echo $this->Form->input('category_id');

I’m using CakePHP 2.0 although this probably applies to other versions.

EDIT

I was nearly there and the answer from Oldskool showed me it was probably possible so I dug into the $this variable and found where it should go.
In the view, use:

$this->viewVars = $this->requestAction('posts/add');

and the select element is populated as in a baked add view (i.e. automatically).

Answer 1

I have a similar construction in one of my own Cake apps. Your approach is correct, make sure the controller fetches the data that your form needs to be aware of. In the above code, Cake should automatically pick it up, if it doesn’t you can ‘force’ the options, by adding the ‘options’ key to the option array, like this:

echo $this->Form->input('category_id', array('options' => $categories));

As a fail-safe you could add a check, like this:

if(!isset($categories) || empty($categories)) {
    // Do whatever you want here to catch the lack of $categories, like:
    die("No categories specified in controller!");
} else {
    echo $this->Form->input('category_id', array('options' => $categories));
}