Parent/child relationship in custom module

Question

I am adding a custom "category" model with children items in my module.

To add children I need to fetch collection from this "mycategories" module. How do I get a collection of categories when adding children items to show in a dropdown in the backend?

I tried using the model collection factory method:

$collection = $this->mymodulemodelFactory->create();

But I think it is for getting collection of the same model.

Note: By category and its children, i dont mean that they are Magento Catalog categories. They can be anything like Palettes and colors, Font family and fonts etc.

I edited your question and title based on your comment, to make clear that it is not about Magento categories. I'm still not sure how "show in a dropdown" and "add children" is relevant since you are asking for how to fetch a collection. If you need more help, please add more specific information about what you have and what you try to achieve. — Fabian Schmengler, Sep 07 '16 at 06:37

Siarhey Uchukhlebau · Answer 1 · 2016-08-07T10:55:16.897

List of all categories with sub-categories as an option array (with opt-group):

If you want to get the category tree, just use the method toOptionArray of the \Magento\Catalog\Ui\Component\Product\Form\Categories\Options class located in vendor/magento/module-catalog/Ui/Component/Product/Form/Categories/Options.php like this:

/**
 * @var \Magento\Catalog\Ui\Component\Product\Form\Categories\Options
 */
protected $categoriesOptions;

/**
 * @param \Magento\Catalog\Ui\Component\Product\Form\Categories\Options $categoriesOptions
 */
public function __construct(
    \Magento\Catalog\Ui\Component\Product\Form\Categories\Options $categoriesOptions
) {
    $this->categoriesOptions = $categoriesOptions;
}

public function getCategories()
{
    $values = $this->categoriesOptions->toOptionArray();

    return $values;
}

Result in this case should look like this (options with opt-groups):

List of all categories as an option array:

Try this:

/**
 * @var \Magento\Catalog\Model\CategoryFactory
 */
protected $categoryFactory;

/**
 * @param \Magento\Catalog\Model\CategoryFactory $categoryFactory
 */
public function __construct(
    \Magento\Catalog\Model\CategoryFactory $categoryFactory
) {
    $this->categoryFactory = $categoryFactory;
}

public function getCategories()
{
    /** @var \Magento\Catalog\Model\ResourceModel\Category\Collection $collection */
    $collection = $this->categoryFactory->create()->getCollection()->addAttributeToSelect('name');
    $values = $collection->toOptionArray(); // or use method toArray

    return $values;
}

Result should look like this:

List of all categories with data as an array:

To get all the category data just replace toOptionArray() to toArray():

$values = $collection->toArray();

i am not asking about Magento categories, i just want to show dropdown items as collection of another module. — HungryDB, Sep 07 '16 at 05:57

score 0 · Answer 2 · edited Jun 15 '20 at 08:30

You have to implement this parent-child relationship and a method like getChildCollection() yourself.

Usually you will have a database column parent_id and to load the children of a given parent, you filter by the parent id.

Example method for a resource model:

public function getChildCollection($parent)
{
    $collection = $this->collectionFactory->create();
    $collection->addFieldToFilter('parent_id', $parent->getId());
    return $collection;
}

Parent/child relationship in custom module

2 Answers2

List of all categories with sub-categories as an option array (with opt-group):

List of all categories as an option array:

List of all categories with data as an array:

Example method for a resource model: