Dynamic form validation in symfony2

Before receiving $_POST information from form submission, I didn't know anything about the number of fields, types or validation rules (whether the field is required, whether 开发者_运维知识库it should be a valid email, etc.)

In ohter words, the validation rules and fields depend on what i receive in $_POST: user creates form fields and defines validation rules by himself.

So I need to set validation rules after I'll receive $_POST

What will be most right method to do this in symfony2?

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The solution was simple: http://symfony.com/doc/current/book/forms.html#adding-validation

(It seems this paragraph was added not long time ago, or i don't know)

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This is exactly the same thing that happens in CollectionType. There the ResizeFormListener instance listens to the preBind event to dynamically add or remove fields. You should do the same.