Symfony2 - Set a selected value for the entity field

Question

I\'m trying to set a selected value inside an entity field. In accordance with many discussions I\'ve seen about this topic, I tried to set the data option but

Answer 1

When you use the query_builder option, and the data option expects an collection instance, and you don't want to touch your controller by adding setDatas for only certain fields, and you already have your querybuilder and the ids of the repopulating options in your form type class, you can repopulate a selection as following:

// Querybuilder instance with filtered selectable options
$entities = $qb_all; 
// Querybuilder instance filtered by repopulating options (those that must be marked as selected)
$entities_selected = $qb_filtered; 

Then in your add() Method

'data' => $entities_selected->getQuery()->getResult(), // Repopulation
'query_builder' => $entities,

EDIT: Real use case example

You want to repopulate a checkbox group rendered with following elements:

Label: What is your favourite meal?

4 Checkboxes: Pasta, Pizza, Spaghetti, Steak

And you want to repopulate 2 Checkboxes:

Pizza, Steak

$qb_all would be a QueryBuilder instance with the all 4 selectable Checkboxes

$qb_filtered would be a new additional QueryBuilder instance with the repopulating Checkboxes Pizza, Steak. So a "filtered" version of the previous one.