Ruby on Rails

  <%= render @parent_categories %>
error:

'nil' is not an ActiveModel-compatible object. It must implement :to_partial_path.

was <%= render @parent_categories %> supposed to call the _category.html.erb partial ? 

On 21 November 2015 at 18:50, fugee ohu <fuge...@gmail.com> wrote:

i'm trying to follow these instructions:

in my categories_controller.rb

def index

@parent_categories = Category.without_parents

in my index.html.erb

<ul>

<%= render @parent_categories %>

</ul>

in my _categories.html.erb

<ul>

<li>

<strong><%= category.name %></strong>

<ul>

<%= render category.categories %>

</ul>

</li>

</ul>

but this doesn't work i get unknown method wihtout_parents and couldn't figure out what without_parents was supposed to be so, i tried changing the line in the controller to @parent_categories = Category.where("parent_id=0") and it was on to the next error, now i get undefined method `categories' for #<Category:0xb1604e2c> My understanding is that in the statement, category is the partial view and categories means the entire collection, so then why doesn't rails recognize the meaning of categories as the entire collection and what's the story with "without_parents" ? ~ thanks, fugee


I am afraid your ideas are so horribly mixed up it is difficult to know where to start.  I think the instructions you are following must be rather poor.  I suggest instead you start by working right through railstutorial.org (which is free to use online) which will show you the basics of Rails in a way which most can follow.

Colin