# Using helper method of another model **URL:** \ **Category:** Rails\ **Created:** [April 6, 2006, 7:22pm UTC](https://www.ruby-forum.com/t/using-helper-method-of-another-model/57040 "2006-04-06T19:22:59Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![r00by\_n00by](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/839c29/32.png) [@r00by\_n00by](https://www.ruby-forum.com/u/r00by_n00by)\ **Post date:** [April 6, 2006, 7:22pm UTC](https://www.ruby-forum.com/t/using-helper-method-of-another-model/57040/1 "2006-04-06T19:22:59Z")
I have a template that belongs to a certain model (model A). I need to call a helper method of a different model (model B). Then I need the helper method of B to call a helper method of model C. I tried using “include” and “require” and using namespaces, but I got “undefined method”. What is the way to do it? ---
**Author:** ![r00by\_n00by](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/839c29/32.png) [@r00by\_n00by](https://www.ruby-forum.com/u/r00by_n00by)\ **Post date:** [April 6, 2006, 8:26pm UTC](https://www.ruby-forum.com/t/using-helper-method-of-another-model/57040/2 "2006-04-06T20:26:44Z")
r00by n00by wrote: > I have a template that belongs to a certain model (model A). I need to > call a helper method of a different model (model B). Then I need the > helper method of B to call a helper method of model C. > I tried using “include” and “require” and using namespaces, but I got > “undefined method”. What is the way to do it? Disclaimer: a newb writes: Try helper :modelB in your A controller to allow B’s helper to be accessible in A. Not sure bout the nesting, but might work. Alternatively, i think if you put the helper methods in application\_helper.rb they should be able to see each other. Hope this helps Chris T ---
**Author:** ![r00by\_n00by](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/839c29/32.png) [@r00by\_n00by](https://www.ruby-forum.com/u/r00by_n00by)\ **Post date:** [April 6, 2006, 11:07pm UTC](https://www.ruby-forum.com/t/using-helper-method-of-another-model/57040/3 "2006-04-06T23:07:43Z")
Chris T wrote: > r00by n00by wrote: > > > I have a template that belongs to a certain model (model A). I need to > > call a helper method of a different model (model B). Then I need the > > helper method of B to call a helper method of model C. > > I tried using “include” and “require” and using namespaces, but I got > > “undefined method”. What is the way to do it? > > Disclaimer: a newb writes: > Try helper :modelB in your A controller to allow B’s helper to be > accessible in A. Not sure bout the nesting, but might work. > Alternatively, i think if you put the helper methods in > application\_helper.rb they should be able to see each other. > Hope this helps > Chris T I tried “helper :modelB” and it did help a little. I can now call BHelper.foo from a template that belongs to A , but now I have “undefined method” when I try to call link\_to inside BHelper.foo . AHelper also has a method called “foo” so I can’t drop the namespace. ---
**Author:** ![r00by\_n00by](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/839c29/32.png) [@r00by\_n00by](https://www.ruby-forum.com/u/r00by_n00by)\ **Post date:** [April 7, 2006, 12:07am UTC](https://www.ruby-forum.com/t/using-helper-method-of-another-model/57040/4 "2006-04-07T00:07:42Z")
r00by n00by wrote: > I have a template that belongs to a certain model (model A). I need to > call a helper method of a different model (model B). Then I need the > helper method of B to call a helper method of model C. > I tried using “include” and “require” and using namespaces, but I got > “undefined method”. What is the way to do it? Put the methods you need across models in the ApplicationHelper. ---
**Author:** ![r00by\_n00by](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/839c29/32.png) [@r00by\_n00by](https://www.ruby-forum.com/u/r00by_n00by)\ **Post date:** [April 7, 2006, 12:35am UTC](https://www.ruby-forum.com/t/using-helper-method-of-another-model/57040/5 "2006-04-07T00:35:09Z")
These are good solutions and maybe I will use them, but I would still like to know how to call link\_to from BHelper.foo (using namespace when defining the method). I thought ActionView::Helpers::UrlHelper::link\_to should work. It didn’t. ---
**Author:** ![r00by\_n00by](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/839c29/32.png) [@r00by\_n00by](https://www.ruby-forum.com/u/r00by_n00by)\ **Post date:** [April 7, 2006, 12:04am UTC](https://www.ruby-forum.com/t/using-helper-method-of-another-model/57040/6 "2006-04-07T00:04:14Z")
r00by n00by wrote: > > > > > I tried “helper :modelB” and it did help a little. I can now call > BHelper.foo from a template that belongs to A , but now I have > “undefined method” when I try to call link\_to inside BHelper.foo . > AHelper also has a method called “foo” so I can’t drop the namespace. Not sure, but can you refer to fully qualified names ModelA :: foo (sorry don’t have Agile book to hand at the moment). Alternatively, maybe you will just have to rename some of the methods afoo, bfoo etc. Sorry can’t be more of a help at the moment. Chris T