Add confirmed field to admin customer form

Question

I've added the confirmed field with a

view\adminhtml\ui_component\customer_form.xml:

<?xml version="1.0" encoding="UTF-8"?>
<form xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Ui:etc/ui_configuration.xsd">
    <fieldset name="customer">
        <field name="confirmed">
            <argument name="data" xsi:type="array">
                <item name="options" xsi:type="object">Magento\Config\Model\Config\Source\Yesno</item>
                <item name="config" xsi:type="array">
                    <item name="source" xsi:type="string">customer</item>
                    <item name="label" translate="true" xsi:type="string">Confirmed</item>
                    <item name="sortOrder" xsi:type="string">210</item>
                    <item name="formElement" xsi:type="string">select</item>
                    <item name="dataType" xsi:type="string">select</item>
                </item>
            </argument>
        </field>
    </fieldset>
</form>

The field is shown, but not with correct values, always the default one. Now I need to change the customer retrieved data to get this field with Yes if the customer is already confirmed and No if not confirmed.

How can I process the data for the form?

EDIT: I have also created an observer (to set the correct value) using the

customer_load_after in adminhtml/events.xml

<event name="customer_load_after">
    <observer name="customerLoad" instance="<Vendor>\<Module>\Observer\Backend\CustomerLoadObserver" />
</event>

For testing, I tried changing the customer firstname. But it only worked for the admin page title (in the h1 class="page-title"), the customer form fields still have the values from database.

Answer 1

I've found that after v2.3 the admin edit customer info was not using the Magento\Framework\Model\AbstractModel, so it was not dispatching $this->_eventPrefix . '_load_after'.

Instead, it uses the Magento\Customer\Model\Customer\DataProviderWithDefaultAddresses. After this finding this was easy to extend it. In the di.xml

<preference for="Magento\Customer\Model\Customer\DataProviderWithDefaultAddresses" type="Vendor\Module\Model\DataProvider\CustomerDataProviderWithDefaultAddresses"/>

Then created the class Vendor\Module\Model\DataProvider\CustomerDataProviderWithDefaultAddresses with:

namespace Vendor\Module\Model\DataProvider;
class CustomerDataProviderWithDefaultAddresses extends \Magento\Customer\Model\Customer\DataProviderWithDefaultAddresses
{
    public function getData()
    {
        $res = parent::getData();
        // code ...
        // $res is an array [entity_id] => [entity data]
        return $res;
    }
}