Nested collection fields in Sonata Admin (2.3)

Question

I\'m having problems creating my form for creating a course. This is a part of my database scheme for which I\'m trying to create a form:

So which I\'m trying t

Answer 1

public function getChildFormBuilder(FormBuilder $formBuilder, $elementId)
{
    foreach (new FormBuilderIterator($formBuilder) as $name => $formBuilder) {
        if ($name == $elementId) {
            return $formBuilder;
        }
    }
    return;
}

Dumping the name and element id within the loop won't accomplish anything. Your application obviously crashes when there is nothing to iterate - it then walks through the loop, exits and goes to the last line where NULL is returned.

I suggest you dump the element id just after the loop, like the following. The use of debug_backtrace might also help:

public function getChildFormBuilder(FormBuilder $formBuilder, $elementId)
{
    foreach (new FormBuilderIterator($formBuilder) as $name => $formBuilder) {
        if ($name == $elementId) {
            return $formBuilder;
        }
    }

var_dump(__METHOD__);
var_dump($elementId);
var_dump(debug_backtrace());

    return;
}