Hello, please forgive me if this answer is obvious! I''m new to Rails
this week.
I have two database tables, and the associated scaffolding, controllers,
models and views. The first is service_provider, which holds a list of
service providers. The second is service_provider_countries which is a
table of countries (obvious perhaps).
In views/service_providers/new.html.erb I have a form, that allows the
you to create a new service provider (name, country, description).
Which looks like so:
<h1>New Service Provider</h1>
<% form_for(@service_provider) do |f| %>
<%= f.error_messages %>
<p>
<%= f.label :Name %><br />
<%= f.text_field :Name %>
</p>
<p>
<%= f.label :Country %><br />
<%= f.text_field :Country %>
</p>
<p>
<%= f.label :Description %><br />
<%= f.text_field :Description %>
</p>
<p>
<%= f.submit ''Create'' %>
</p>
<% end %>
This works as expected, however, I want to modify the form so it lists
all the countries in a select box from the service_provider_countries
table.
In views/service_provider_countries/index.html.erb I added:
<%= select ("CountryISO", "id",
@service_provider_countries.map {|u|
[u.ISO,u.ISO]}) %>
Which works as expected, producing a select box of all the countries.
However, when I copy this bit of code and put it into
views/service_providers/new.html.erb it does not work, producing the
error:
You have a nil object when you didn''t expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.map
I understand the error to mean that view/service_providers does not have
access to the (controller?model?) service_provider_countries, could you
please explain how I might do this? Thank you and apologies for the
long-winded post.
--
Posted via http://www.ruby-forum.com/.
Just Dawson wrote:> Hello, please forgive me if this answer is obvious! I''m new to Rails > this week. > > I have two database tables, and the associated scaffolding, controllers, > models and views. The first is service_provider, which holds a list of > service providers. The second is service_provider_countries which is a > table of countries (obvious perhaps). > > In views/service_providers/new.html.erb I have a form, that allows the > you to create a new service provider (name, country, description). > > Which looks like so: > > <h1>New Service Provider</h1> > > <% form_for(@service_provider) do |f| %> > <%= f.error_messages %> > <p> > <%= f.label :Name %><br /> > <%= f.text_field :Name %> > </p> > <p> > <%= f.label :Country %><br /> > <%= f.text_field :Country %> > </p> > <p> > <%= f.label :Description %><br /> > <%= f.text_field :Description %> > </p> > <p> > <%= f.submit ''Create'' %> > </p> > <% end %> > > This works as expected, however, I want to modify the form so it lists > all the countries in a select box from the service_provider_countries > table. > > In views/service_provider_countries/index.html.erb I added: > > <%= select ("CountryISO", "id", @service_provider_countries.map {|u| > [u.ISO,u.ISO]}) %> > > Which works as expected, producing a select box of all the countries. > > However, when I copy this bit of code and put it into > views/service_providers/new.html.erb it does not work, producing the > error: > > You have a nil object when you didn''t expect it! > You might have expected an instance of Array. > The error occurred while evaluating nil.map > > I understand the error to mean that view/service_providers does not have > access to the (controller?model?) service_provider_countries, could you > please explain how I might do this? Thank you and apologies for the > long-winded post.the thing is that@service_provider_countris is a instance variable declared in the new action of the ServiceProviderCountries controller in the new action of the ServiceProviders, you can do @service_provider_countries = ServiceProviderCountries.all and that will do the work you want. but a better approach could be to do <%= f.collection_select :service_provider_country_id, ServiceProviderCountries.all, :id, :name, :include_blank => ''None'' %> Remember to declare the relationship in the model tables and to create the foreing key in the migrations -- Posted via http://www.ruby-forum.com/.
Rodrigo Dominguez wrote:> Just Dawson wrote: >> Hello, please forgive me if this answer is obvious! I''m new to Rails >> this week. >> >> I have two database tables, and the associated scaffolding, controllers, >> models and views. The first is service_provider, which holds a list of >> service providers. The second is service_provider_countries which is a >> table of countries (obvious perhaps). >> >> In views/service_providers/new.html.erb I have a form, that allows the >> you to create a new service provider (name, country, description). >> >> Which looks like so: >> >> <h1>New Service Provider</h1> >> >> <% form_for(@service_provider) do |f| %> >> <%= f.error_messages %> >> <p> >> <%= f.label :Name %><br /> >> <%= f.text_field :Name %> >> </p> >> <p> >> <%= f.label :Country %><br /> >> <%= f.text_field :Country %> >> </p> >> <p> >> <%= f.label :Description %><br /> >> <%= f.text_field :Description %> >> </p> >> <p> >> <%= f.submit ''Create'' %> >> </p> >> <% end %> >> >> This works as expected, however, I want to modify the form so it lists >> all the countries in a select box from the service_provider_countries >> table. >> >> In views/service_provider_countries/index.html.erb I added: >> >> <%= select ("CountryISO", "id", @service_provider_countries.map {|u| >> [u.ISO,u.ISO]}) %> >> >> Which works as expected, producing a select box of all the countries. >> >> However, when I copy this bit of code and put it into >> views/service_providers/new.html.erb it does not work, producing the >> error: >> >> You have a nil object when you didn''t expect it! >> You might have expected an instance of Array. >> The error occurred while evaluating nil.map >> >> I understand the error to mean that view/service_providers does not have >> access to the (controller?model?) service_provider_countries, could you >> please explain how I might do this? Thank you and apologies for the >> long-winded post. > > the thing is that@service_provider_countris is a instance variable > declared in the new action of the ServiceProviderCountries controller > > in the new action of the ServiceProviders, you can do > @service_provider_countries = ServiceProviderCountries.all > > and that will do the work you want. > > but a better approach could be to do > > <%= f.collection_select :service_provider_country_id, > ServiceProviderCountries.all, :id, :name, :include_blank => ''None'' %> > > Remember to declare the relationship in the model tables and to create > the foreing key in the migrationsThank you for your help, I modified /controllers/service_providers_controller.rb as follows: def new @service_provider = ServiceProvider.new @service_provider_countries = ServiceProviderCountry.all respond_to do |format| format.html # new.html.erb format.xml { render :xml => @service_provider } end end This now works as I had hoped. Thank you again. -- Posted via http://www.ruby-forum.com/.