CODEWITHSUNDEEP
ruby-on-railsrubyruby-on-rails-4parameterslink-to
fr3d0
fr3d0

Reputation: 225

passing parameters through link_to method in ruby on rails 4

i have an index view that shows all available classes i want a link to "sign up for class" that redirects me to the "sign up" form and fill up some other values and when the sign up is created it saves the values that i filled up plus the foreign key of the class i just passed via the link to method

classes index:

<h1>Listof classes</h1>

<table>
  <thead>
    <tr>
      <th>id</th>
      <th>Name</th>
      <th>Description</th>
      <th>Actions</th>
    </tr>
  </thead>
  <tbody>
    <% @classes.each do |class| %>
      <tr>
        <td><%= class.id %></td>
        <td><%= class.name %></td>
        <td><%= class.description %></td>
        <td><%= link_to 'sign up!', new_sign_up_path(:class_id => class.id), method: :post %></td> 
      </tr>
    <% end %>
  </tbody>
</table>

sign_up controller:

class SignUpsCOntroller < ApplicationController
  before_action :set_sign_ups, only: [:show, :edit, :update, :destroy]

  # GET /sign_ups/new
  def new
    @sign_up = SignUp.new
  end

    def set_sign_ups
      @sign_up = SignUp.find(params[:id])
    end

    def sign_up_params
      params.require(:sign_up).permit(:date, :status, :type, :class_id)
    end
end

and my sign ups form:

<%= form_for(@sign_up) do |f| %>

  <div class="field">
    <%= f.label :date %><br>
    <%= f.date_select :date %>
  </div>
  <div class="field">
    <%= f.label :status %><br>
    <%= f.check_box :status %>
  </div>
  <div class="field">
    <%= f.label :type %><br>
    <%= f.number_field :type %>
  </div>
    <div class="field">
    <%= f.hidden_field :class_id %>
  </div>
  <div class="actions">
    <%= f.submit %>
  </div>
<% end %>

when i save it it doesn't save the the class_id... i've tried parsing it to integer i've tried it without the hidden field but it allways passes it as blank en saving... any ideas?

Upvotes: 1

Views: 1239

Answers (1)

Shadwell
Shadwell

Reputation: 34774

You are just passing in params[:class_id] with your extra parameter on the link_to. Your form however is for an object with a class_id attribute so it is expecting your @sign_up object to have a class_id attribute.

Basically for your new action you'll need to set up @sign_up with the class_id for it from the parameters:

def new
  @sign_up = SignUp.new
  @sign_up.class_id = params[:class_id] if params.has_key?(:class_id)
end

This will set the class_id to the parameter passed in from the link_to url.

Then your form should work okay because the f.hidden_field will look at the current value of class_id on @sign_up and set that as the value of the input. It doesn't matter that you haven't saved it at this point - the form_for will use the unsaved state to populate the inputs.

Upvotes: 2

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