I am building an application using Symfony 2, and one of the pages contains a large form, which has a number of fixed fields but also a number of fields whose presence and number depends entirely on related data taken from the DB. More specifically, the form poses a number of questions, and the questions themselves come from the DB, having different text and IDs. The answers need to be stored in the DB, linked to the questions.
I've read up on how Symfony handles forms (Basic Symfony Forms), including the relationship between a Form object and the data object backing it, creating Fields from the Form object, and validating input according to rules applied to the Form object.
Since I don't want a fixed Form object I looked at how you're meant to dynamically modify Forms (Dynamic Symfony Forms), but the examples there seem to be about choosing whether to show certain pre-defined fields, or controlling the options in the fields, not completely generating new fields from scratch, which is what I want.
I had a look at the Symfony page on Data Transformers, and it seemed relevant, but I couldn't quite get my head around how it would help me. They seem more about mapping a Form object to an Entity than mapping complex form submissions to a Form object.
I did see this SO answer where the object backing the Form object is just an array, which also seemed relevant: I thought that maybe the answer was to generate some anonymous object with the dynamic fields in, and then make a form from that, but I don't see how I'd set up Symfony validation on it, and my form is not completely different each time, so doesn't need to be entirely anonymous.
What is the best way to achieve this using Symfony 2, ideally without giving up such framework benefits as easy validation etc?
EDIT I hadn't heard of Symfony Form Collections before, and it looks like this might do what I want - each Question in my case would map to an individual subform object. I'll update again if I try it out successfully.
