How to input a calculated value after form validation in zf2 - forms

Question

I’m developing a form in zf2 and I want to calculate a value based upon user input and set it in a field after the form has validated. In the form, there is a firstName field and a lastName field; and I want to use the validated input to calculate a value to populate in a fullName field.
I assume I want to set the value something like this, but haven’t found the right code for setting the "element" that gets sent to the database:
public function addAction()
{
$objectManager = $this->getServiceLocator()->get('Doctrine\ORM\EntityManager');
$form = new AddMemberForm($objectManager);
$member = new Member();
$form->bind($member);
$request = $this->getRequest();
if ($request->isPost()) {
$form->setData($request->getPost());
if ($form->isValid()) {
// develop full name string and populate the field
$calculatedName = $_POST['firstName'] . " " . $_POST['lastName'];
$member->setValue('memberFullName', $calculatedName);
$this->getEntityManager()->persist($member);
$this->getEntityManager()->flush();
return $this->redirect()->toRoute('admin-members');
}
}
return array('form' => $form);
}

Answer 1

Doctrine's built-in Lifecycle Callbacks are perfectly fits for handling such requirement and I strongly recommend to use them.
You just need to correctly annotate the entity.
For example:
<?php
/**
* Member Entity
*/
namespace YourNamespace\Entity;
use Doctrine\ORM\Mapping as ORM;
use Doctrine\ORM\Event\LifecycleEventArgs;
/**
* #ORM\Table(name="members")
* #ORM\Entity
* #ORM\HasLifecycleCallbacks
*/
class Member
{
// After all of your entity properies, getters and setters... Put the method below
/**
* Calculate full name on pre persist.
*
* #ORM\PrePersist
* #return void
*/
public function onPrePersist(LifecycleEventArgs $args)
{
$this->memberFullName = $this->getFirstName().' '.$this->getLastName();
}
}
With this way, memberFullName property of the entity will be automatically populated using first and last names on entity level just before persisting.
Now you can remove the lines below from your action:
// Remove this lines
$calculatedName = $_POST['firstName'] . " " . $_POST['lastName'];
$member->setValue('memberFullName', $calculatedName);

Answer 2

Foozy’s excellent answer provides a solution that works for an add action, and the response to my comment directed me to the following solution that works for both add and edit actions:
<?php
/**
* Member Entity
*/
namespace YourNamespace\Entity;
use Doctrine\ORM\Mapping as ORM;
use Doctrine\ORM\Event\PreFlushEventArgs;
/**
* #ORM\Table(name="members")
* #ORM\Entity
*/
class Member
{
// After all of your entity properies, getters and setters... Put the method below
/**
* Calculate full name on pre flush.
*
* #ORM\PreFlush
* #return void
*/
public function onPreFlush(PreFlushEventArgs $args)
{
$this->memberFullName = $this->getFirstName().' '.$this->getLastName();
}
}