Want to directly access MODEL from VIEW. Can;t :(

rubyonrails-talk
1

Hi I have a model called navbar. It does not have a view or a controller defined.

create_table :navbars do |t|       t.string :name       t.string :display_name       t.string :url       t.string :group_by_module       t.boolean :default_link       t.integer :sort_order

And in the model I have written few methods.

class Navbar < ActiveRecord::Base def all_modules   NavBar.find (:display_name, :url, :conditions => {:name => 'module_bar'}, :order => 'sort_order') end def associated_quick_links (selected_module)   NavBar.find (:display_name, :url, :default_link, :conditions => {:name => 'quick_links_bar', :group_by_module => selected_module}, :order => 'sort_order') end def associated_module (selected_quick_link)   NavBar.find (:group_by_module, :conditions => {:name => 'quick_links_bar', :display_name => selected_quick_links}) end end

QUESTION --- I want to access these methods from views directly. When I do <%= debug navbar.all_modules %> it fails. It cannot find the navbar.

Can someone please guide me? Thanks in advance

2

For accessing model method from view , you can define self methods in model and than directly access by ModelName.methodName

For example

class Navbar < ActiveRecord::Base

def self.all_modules Ur stuff

end

end

in view <% Navbar.all_modules %>

3

Did what you said.. Now getting error --- "undefined local variable or method `navbar' for #<ActionView::Base:0x4dfce0c>"

4

can you tell me what you did exactly ?

5

Hi

QUESTION — I want to access these methods from views directly. When I do <%= debug navbar.all_modules %> it fails. It cannot find the navbar.

This will work fine only if you have navbar as an object of your Navbar model, confirm whether you have done the same. As I observe that your method in model does not have anything related to specific object of the class, you can have it as a class method by defining it as self.all_modules. This can be directly used by Navbar.all_modules

Note: One should not use model methods in views directly. Use controller objects or helpers for the same.

  • Nayak
6

agree with Nayak, If you didn’t create the object navbar than it will through the exception that is in your case.

or define static methods like I did and use directly by model name.

Avoid direct model’s method calls in view , use helper file or controller as suggested by Nayak.

~N A R E N

7

This is like a reference table which doesnt need a controller :expressionless: And it is a reftable for what links to display on screen.

This is what I did finally.

class Navbar < ActiveRecord::Base def self.all_modules   NavBar.find (:display_name, :url, :conditions => {:name => 'module_bar'}, :order => 'sort_order') end def self.associated_quick_links (selected_module)   NavBar.find (:display_name, :url, :default_link, :conditions => {:name => 'quick_links_bar', :group_by_module => selected_module}, :order => 'sort_order') end def self.associated_module (selected_quick_link)   NavBar.find (:group_by_module, :conditions => {:name => 'quick_links_bar', :display_name => selected_quick_links}) end end

And I am still getting undefined local variable or method `navbar' for #<ActionView::Base: 0x4be1140> Extracted source (around line #2): 1: <div id="content"> 2: <%= debug navbar.all_modules %>

Please help

8

ok let me explain you in your code following is your code 1:

2: <%= debug navbar.all_modules %> now the navbar is undefined , please replace navbar to Navbar capital N that is your Model name see in this line class Navbar < ActiveRecord::Base

now try this and let me know

~N A R E N

9

<div id="content"> <%= debug NavBar.all_modules %>

Now it gives

uninitialized constant ActionView::Base::CompiledTemplates::NavBar Extracted source (around line #2): 1: <div id="content"> 2: <%= debug NavBar.all_modules %>

10

<div id="content"> <%= debug NavBar.all_modules %>

According to your previous posts the class is called Navbar, so you need to type exactly that. Not navbar, NavBar, NAvBaR or anything like that.

Fred

11

In the controller for the action you are testing, did you create an instance of your Navbar class? You are defining a Navbar class, but a class without an instance is fairly useless... Something like:

@navbar = Navbar.new

If so, then the view code as you had it:

<%= @navbar.all_modules %>

should have an instance of Navbar to work with. Your all_modules method inside Navbar cons a little dubious though...

12

Well.. I am using it in application.html.erb --> layouts. So where should I create the instance?

13

NavBar is a reference table whose content needs to be accessed in all VIEWS. This includes the application layout too. Can you please guide which is the best way to model this??? + where to initialize an instance?

14

If you want to initialise the Navbar instance somewhere that has to be accessed by all views (or the layout), put it in the application controller as a before_filter. For example:

class ApplicationController < ActionController::Base

  # Some other stuff

  before_filter :get_navbar

  def get_navbar     @navbar = Navbar.new   end

  # More stuff

end

Then in you view or layout you can access methods using the syntax as outlined earlier:

<%= @navbar.all_modules %>

15

Have you tried it this way yet??? (capital N only!)

<%= debug Navbar.all_modules %>