6
Ciao io sto affrontando questo errore, completamente nuovo alle rotaie figura quindi non posso che cosa sta causandometodo non definito `map 'per nil: NilClass, che cosa causa questo?
mia newBook.html.erb
<html>
<head>
<title> new Book </title>
</head>
<body>
<h1><%= @hello_message %></h1>
<h1>Add new book</h1>
<%= form_tag :action => 'create' %>
<p>
<label for="book_title">Title</label>:
<%= text_field 'book', 'title' %>
</p>
<p>
<label for="book_price">Price</label>:
<%= text_field 'book', 'price' %>
</p>
<p>
<label for="book_subject">Subject</label>:
<%= collection_select(:book,:subject_id,@subjects,:id,:name) %>
</p>
<p>
<label for="book_description">Description</label>
<br/>
<%= text_area 'book', 'description' %>
</p>
<%= submit_tag "Create" %>
<%= end_form_tag %>
<%= link_to 'Back', {:action => 'list'} %>
</body>
</html>
mio libro modello: book.rb
class Book < ActiveRecord::Base
attr_accessible :title, :price,:description , :created_at
belongs_to :subject
validates_presence_of :title
validates_numericality_of :price, :message=>"Error Message"
end
il mio modello di oggetto: subject.rb
class Subject < ActiveRecord::Base
attr_accessible :name
has_many :book
end
traccia dello stack è:
actionpack (3.2.13) lib/action_view/helpers/form_options_helper.rb:364:in `options_from_collection_for_select'
actionpack (3.2.13) lib/action_view/helpers/form_options_helper.rb:600:in `to_collection_select_tag'
actionpack (3.2.13) lib/action_view/helpers/form_options_helper.rb:191:in `collection_select'
app/views/home/newBook.html.erb:19:in `_app_views_home_new_ook_html_erb__299261930_24178164'
actionpack (3.2.13) lib/action_view/template.rb:145:in `block in render'
activesupport (3.2.13) lib/active_support/notifications.rb:125:in `instrument'
actionpack (3.2.13) lib/action_view/template.rb:143:in `render'
# -- snipped --
Se si tratta di RoR, perché taggare con 'java'? – fge
Incolla il codice del controller. –
@fge Nessun tag [tag: java] nella cronologia delle revisioni. (?) – Substantial