I'm working with Symfony2 to set up a form, where a Shelf-Entity can be edited.
A shelf contains a collection of Readable-Entities (e.g. Book, Magazine, etc. - all inherit from Readable).
The user has the possibility to add more Readable-Entities (the form is extended via JavaScript) and from a dropdown he can select the type of Readable he wants to add. Depending on the selected dropdown-value, different form fields are rendered. So far so good.
Now, when the form is submitted to the server, depending on the Readable-Type the user selected in the form, a different entity-type should be instantiated. If I don't do anything, Symfony just instantiates the base class Readable (and not Book, Magazine, etc.).
How can I tell Symfony to instantiate the correct type of Readable depending on the selected value from the dropdown?
I tried with FormEvent-Listeners, but:
- in PRE_SUBMIT I only get an array containing the "raw" form data with $event->getData(), i.e. no entities have been instatiated so far. However, at this stage, I still have access to value of the dropdown.
- in SUBMIT the form data was already assigned to the appropriate entities. Also the new Readable was already instatiated with the base Readable-Class. But now, I cannot access anymore the value from the dropdown.
What is the correct way to do this?
EDIT
Added a minimal Code-Example for the Shelf FormType:
https://gist.github.com/anonymous/401495b701982adafb96
Code for infinite_form_polycollection:
https://gist.github.com/anonymous/b5f0ed10ca9c52177f01
