Hi, I'm implementing some nested forms with Rails 2.3 which works pretty well as long as I only have to edit the objects that are already associated to the original object. I'm not sure though how to implement an "Add new object" button which adds another associated object. Unfortunately I can't pre-build another attribute while loading the form, which would be the standard way presented in the example form of "What's new in Rails 2.3". The reason why this wouldn't work for me is that the user first has to choose which kind of object he's about to add, so the application knows which select options to generate the user is able to choose from to configure the newly created object afterwards. One way to go presented by Ryan B.' in his Railscasts (but designed for Rails 2.2) was to dynamically load an object with a "link_to_function" request and render it to the fields_for block: Within the partial associated_object.html.erb this would look like <% fields_for "object[associated_object]", associated_object do | object_form| %> ... <% end %> ...with an iterator named "associated_object". Within the view there's: link_to_function "name" do |page| page.insert_html :bottom, :associated_objects, :partial => 'associated_object', :object => AssociatedObject.new end Unfortunately I don't understand thoroughly how this one's working so I can't transfer it to the Rails 2.3 situation where the view looks like this: <% f.fields_for :associated_objects do |associated_object_form| %> <div class="associated_object"> <%= associated_object_form.object.name %> ... So what I want to do is: a) provide a "New" button to dynamically insert a new associated_object into the view (as done in the Rails 2.2 example) b) load not just any object into the nested form as done above, but a specific one the user chooses from a select box before clicking "New" I'd be very thankful for any advice!! Perhaps there are good examples on the web? I tried to understand Eloy's example, but it's quite difficult. Best regards
on 2009-03-26 18:18
on 2009-03-26 20:58
on 2009-03-27 12:30
Thanks very much, yeah I'll try to deal with that subject in time. In the meanwhile I'd be happy enough to find a Rails-like way to implement a "New" Button which calls a controller action and passes the value of a select tag to that action. That's not the nicest workaround, but it should work. Or I'll just set up the view component as I did in Rails 2.2. At least I don't have to add setters to the model and Rails 2.3 manages that automatically. Best regards
on 2009-03-27 12:54
> Or I'll just set up the view component as I did in Rails 2.2. At least > I don't have to add setters to the model and Rails 2.3 manages that > automatically. When Rails 2.3 got released, the first thing I didn't was try to migrate my former nested form integration to Rails' builtin system, but it failed, so I reverted back. If you are concerned with the 15 loc added to the model for the new_whatever_attribute= and so on, well actually using metaprogramming, you easily extract this into a plugin and share the code between various models. I think I will follow this path instead of using rails' builtin nested form support.
on 2009-03-27 14:10
Fernando P. wrote: > If you are concerned with the 15 loc added to the model for the > new_whatever_attribute= and so on, well actually using metaprogramming, > you easily extract this into a plugin and share the code between various > models. I think I will follow this path instead of using rails' builtin > nested form support. Having looked at it overnight I can see that the new stuff in 2.3 treats habtm just like hm. So that if for example you have many users and many roles and many-to-many relationship between them and you try to use the new stuff to add a role to a user from a select list it will add a copy of the role to the roles table. If you've got a unique index on the non id identifier, like the name, then you'll be in trouble. It will also issue updates to things it shouldn't. I've cleaned it out of my code. But the jscript stuff in the examples for adding new records is quite useful, I'm fiddling with it now to make it work with old-style nested forms for adding m-2-m links. John S.