Getting the object in fields_for

rubyonrails-talk
1

I'm using the fields_for helper with accepts_nested_attributes_for The System model has_many children.

If I do this in my haml template:

-form_for @system do |s|     =s.text_field :name

    -s.fields_for :children do |child_fields|             =child_fields.text_field :name

all is fine. The fields_for iterates over all children and puts the correct data in the fields.

But...what I want to do is access the child object in that loop. With normal fields_for I could do:             =child_fields.object.foo() within the loop, but that no longer works since child_fields.object is nil. How do I access the child object? Do I just have to revert to creating a separate iteration over the child objects?

2

I think I'm making life hard for myself.

Just browsed through the form_helper.rb code and found what was happening.

     def object         @object || @template_object.instance_variable_get("@# {@object_name}")       rescue NameError         # As @object_name may contain the nested syntax (item [subobject]) we         # need to fallback to nil.         nil      end

So when it's a nested object I get nil.

InstanceTag goes through a bunch of acrobatics in initialize to get the actual object values.

Still doesn't give me any easy way to access the object of the FormBuilder.

3

Ah! You're right.

I was passing the child_fields object to a partial and that's where it was not working. I've pulled the code out of the partial and it works fine.

Cheers.

4

Hi stuart.coyle

Ah! You're right.

I was passing the child_fields object to a partial and that's where it was not working. I've pulled the code out of the partial and it works fine.

Cheers.

    Even in that case it will work.Do like <%= render :partial => 'partial_name',:locals => {:f => child_fields}    And now in partial f.object

Sijo K George