Exporting one to many relationship on sonata admin - symfony

Question

I have tried to search online for a definite solution to this question but there's really no concrete solution for newbies out there.
I have an Entry which has many EntryListing. In my EntryAdmin listMapper, i comfortably can list entries by a statement as simple as
->add('listings')
which simply returns the listings as defined in the EntryListing __toString() function.
Is there a way to achieve the same when exporting the data by overiding the getExportFields() functions as below:
public function getExportFields()
{
return array('name','tel','email','deviceType','postedOn','createdAt','facilitator','listings');
}
Your help will be very much appreciated

Answer 1

There is another work around you can add a property in your entity which will get all entry listing related to that and in getter function return __toString() of related ones, I had the same scenario for orders and also need the list if products associated with order so i have done it this way by creating exportProducts in orders entity
protected $exportProducts;
public function getExportProducts()
{
$exportProducts = array();
$i = 1;
foreach ($this->getItems() as $key => $val) {
$exportProducts[] = $i .
') Name:' . $val->getProduct()->__toString()() .
' Size:' . $val->getProductsize() .
.../** Other properties */;
$i++;
}
return $this->exportProducts = join(' , ', $exportProducts);
}
And in order admin class i defined exportProducts property in getExportFields() as
public function getExportFields(){
return array(
'Products'=>'exportProducts',
....// Other properties
);
}
In downloaded csv each order contains the list of products under Products cell as comma separated list