undefined method `model_name' for Tmdb::Movie:Class

问题

I'm using this gem - TMDb - to build a simple app.

When I visit this URL i get the error:

.../movies/97857/movie_reviews/new

Form:

<%= form_for @movie do |movie_form| %>

<%= fields_for :movie_review, @movie.movie_review do |movie_review_fields| %>
  Title : <%= movie_review_fields.text_field :title %>
<% end %>

<%= f.submit %>
<% end %>

Source code

回答1:

form_for expects an ActiveRecord object (which has an instance method called model_name). @movie is a non-ActiveRecord object that comes from the gem you're using and it doesn't have a method called model_name. That's why you get the error.

I see that you also have a Movie model, but that is not what is used here. From your controller:

@movie = Tmdb::Movie.detail(params[:movie_id])

Since I don't know what you're trying to achieve, I can only point out why you get the error.

来源：https://stackoverflow.com/questions/21692437/undefined-method-model-name-for-tmdbmovieclass