Nil object when an array was expected.

rubyonrails-talk
1

Hi there, it's kind of a weird problem. I have a Person model and Person controller. In the new method in my controller I try to retrieve a collection of nationalities. The nationalities are stored in a different table. So retrieving those should be like:

def new     @person = Person.new     @person.name = Name.new     @person.birthday = Date.today     @person.nationality = Nationality.new     nationalities = Nationality.find( :all ) end

Unfortunately when Rails try to access the array in the new.rhtml it's nil. Here, I create a selection list, as follows:

  <p>     <% form_for :gender do |form| %>       <%= form.select( :gender, @genders ) %>     <% end %>   </p>

The weird thing happens when I retrieve the array inside new.rhtml. It's working here.

  <p>     <% form_for :nationality do |form| %>       <%=         @nationalities = Nationality.find( :all )         form.select( :nationality, @nationalities )       %>     <% end %>   </p>

As stated in the new Web Development book those code should normally reside in the controller.

Am I missing something?

Thanks ahead, Christian

2

Try using an instance variable (@nationalities) in the controller instead of a local variable (nationalities). Instance variables are available in the views, but local variables created in the controller method are not.

Jason

3

Thanks Jason, I'm coming from C++ and though I'm probably more used to C++ way of compiler errors. If an variables is not accessible in the current scope why not just state that. But I guess Ruby is on a lot of ways different to C++.

Anyway thanks, that was the solution.

Christian