Rails新手：集合选择和控制器逻辑

Question

I've read many related questions here, but I still don't understand how to do the following: I have a "Country" model and I'd like to create a select form that will allow users to select any of the existing countries in the model, and be redirected to that country's "show" page.

My collection_select logic is:

<%= collection_select(:country, :country_id, Country.all, :id, :name, prompt: 'Select a Country') %>

<%= submit_tag "Find!", redirect_to (country.params[:id])%>

Any help would be appreciated!

Answer 1

Rails uses MVC, so all logic should be in model(skinny controllers, fat models) and you should select your countries something like this @country = Country.find(params[:country_name]) . And then in view its gonna be <%= submit_tag "Find!", redirect_to country_show_path(@country) %> . If I understood your question right this is the answer.

Answer 2

Select form

Create a drop down within your form:

<%= form_tag countries_path, method: :get do %>
    <%= collection_select(:country, :country_id, Country.all, :id, :name, prompt: 'Select a Country') %>
<%= submit_tag %>

In this case I am hitting contries_path and I have specified a GET request. The value selected by the form will be passed to CountriesController#show .

Post to controller

You can find the country, using the value passed to the form, via the params hash:

class CountriesController < ApplicationController
  def show
    @country = Country.find(params[:country][:country_id])
  end
end

Answer 3

You will need both SelectCountryController (or whatever controller you're using to receive the selected country) and your regular CountriesController.

SelectCountryController:

class SelectCountryController < ApplicationController
  def index
    if params[:country_id].present?
      redirect_to country_path(params[:country_id])
    end
  end
end

Select country view (app/views/select_country/index.html.erb)

<%= form_tag "", method: :get do %>
  <%= collection_select(:country, :country_id, Country.all, :id, :name, prompt: 'Select a Country') %>
  <%= submit_tag "Find!" %>
<% end %>

Countries Controller:

class CountriesController < ApplicationController
    def show
      @country = Country.find(params[:id])
    end
end

Don't forget to make sure you have the proper routes in your routes.rb file:

resources :countries
get :select_country, to: "select_country#index"