Create multiselect with source model in UI component

Question

Since Magento 2.1 you have to define a UI component for custom category attributes (See Magento 2.1: how to create category attrbute programmatically?)

I have one multiselect attribute with a custom source model and cannot get it to work. I took available_sort_by as an example and managed to show the attribute with a multiselect input but it has no options, i.e. it is not using my source model.

This is the relevant part of category_form.xml:

 <field name="solr_remove_filters">
 <argument name="data" xsi:type="array">
 <item name="config" xsi:type="array">
 <item name="sortOrder" xsi:type="number">20</item>
 <item name="additionalClasses" xsi:type="string">admin__field-default</item>
 <item name="formElement" xsi:type="string">multiselect</item>
 <item name="source" xsi:type="string">category</item>
 <item name="label" xsi:type="string" translate="true">Remove Filters</item>
 <item name="tooltip" xsi:type="array">
 <item name="link" xsi:type="string">#</item>
 <item name="description" xsi:type="string" translate="true">Hold the CTRL key to select multiple filters</item>
 </item>
 <item name="scopeLabel" xsi:type="string">[STORE VIEW]</item>
 </item>
 </argument>
 </field>

The attribute solr_remove_filters has been added with the following install script:

 $eavSetup->addAttribute(
 Category::ENTITY,
 'solr_remove_filters',
 [
 'type' => 'text',
 'input' => 'multiselect',
 'source' => FilterableProductAttributeSource::class,
 'backend' => FilterableProductAttributeBackend::class,
 'label' => 'Remove Filters',
 'note' => 'Hold the CTRL key to select multiple filters',
 'required' => 0,
 'user_defined' => 0,
 'group' => 'Solr',
 'global' => 0,
 'visible' => 1,
 ]
 );

I have set a debug breakpoint in FilterableProductAttributeSource::getAllOptions() and see that it is executed and returns an array in the form

[
 ['value' => 'value1', 'label' => 'label1'],
 ['value' => 'value2', 'label' => 'label2'],
 ['value' => 'value3', 'label' => 'label3'],
]

which confirms that the source model is instantiated and works.

What do I need to do to populate the UI component with these values?

Answer 1

Found it, thanks to GitHub issue #5438. The source model has to be specified in category_form.xml as well:

 <field name="solr_remove_filters">
 <argument name="data" xsi:type="array">
 <item name="options" xsi:type="object">IntegerNet\Solr\Model\Entity\Attribute\Source\FilterableProductAttribute</item>
 <item name="config" xsi:type="array">
 ...

Just don't ask me why it works without that for available_sort_by and why all this redundancy is necessary...

• fudu: Hi, i dont understand how 'available_sort_by ' work, please help :) magento.stackexchange.com/questions/238037/…

Answer 2

You need to consider source model to display options because you have custom source model if you wants to you can use array backend for source model t display options in admin for category multi select attribute. Your code works because you are telling ui_component that you are going to use following options for you multi select attribute.