How to have a drop down <select> field in a rails form? - ruby-on-rails

Question

I am creating a scaffold -
rails g scaffold Contact email:string email_provider:string
but I want the email provider to be a drop down (with gmail/yahoo/msn as options) and not a text field. How can I do this ?

Answer 1

You can take a look at the Rails documentation . Anyways , in your form :
<%= f.collection_select :provider_id, Provider.order(:name),:id,:name, include_blank: true %>
As you can guess , you should predefine email-providers in another model -Provider , to have where to select them from .

Answer 2

Or for custom options
<%= f.select :desired_attribute, ['option1', 'option2']%>

Answer 3

You create the collection in the Contact controller -
app/controllers/contacts_controller.erb
Adding
#providers = Provider.all.by_name
to the new, create and edit methods, using a scope for the by_name in the Provider model - app/models/provider.rb - for the ordering by name
scope by_name order(:name)
Then in the view - app/views/contacts/_form.html.erb - you use
<%= f.collection_select :provider_id, #providers, :id, :name, include_blank: true %>
For rails forms, I also strongly recommend you look at a form builder like simple_form - https://github.com/plataformatec/simple_form - which will do all the heavy lifting.

Answer 4

This is a long way round, but if you have not yet implemented then you can originally create your models this way. The method below describes altering an existing database.
1) Create a new model for the email providers:
$ rails g model provider name
2) This will create your model with a name string and timestamps. It also creates the migration which we need to add to the schema with:
$ rake db:migrate
3) Add a migration to add the providers ID into the Contact:
$ rails g migration AddProviderRefToContacts provider:references
4) Go over the migration file to check it look OK, and migrate that too:
$ rake db:migrate
5) Okay, now we have a provider_id, we no longer need the original email_provider string:
$ rails g migration RemoveEmailProviderFromContacts
6) Inside the migration file, add the change which will look something like:
class RemoveEmailProviderFromContacts < ActiveRecord::Migration
def change
remove_column :contacts, :email_provider
end
end
7) Once that is done, migrate the change:
$ rake db:migrate
8) Let's take this moment to update our models:
Contact: belongs_to :provider
Provider: has_many :contacts
9) Then, we set up the drop down logic in the _form.html.erb partial in the views:
<div class="field">
<%= f.label :provider %><br>
<%= f.collection_select :provider_id, Provider.all, :id, :name %>
</div>
10) Finally, we need to add the provders themselves. One way top do that would be to use the seed file:
Provider.destroy_all
gmail = Provider.create!(name: "gmail")
yahoo = Provider.create!(name: "yahoo")
msn = Provider.create!(name: "msn")
$ rake db:seed

Answer 5

<%= f.select :email_provider, ["gmail","yahoo","msn"]%>

Answer 6

Please have a look here
Either you can use rails tag Or use plain HTML tags
Rails tag
<%= select("Contact", "email_provider", Contact::PROVIDERS, {:include_blank => true}) %>
*above line of code would become HTML code(HTML Tag), find it below *
HTML tag
<select name="Contact[email_provider]">
<option></option>
<option>yahoo</option>
<option>gmail</option>
<option>msn</option>
</select>

Answer 7

Rails drop down using has_many association for article and category:
has_many :articles
belongs_to :category
<%= form.select :category_id,Category.all.pluck(:name,:id),{prompt:'select'},{class: "form-control"}%>

Answer 8

In your model,
class Contact
self.email_providers = %w[Gmail Yahoo MSN]
validates :email_provider, :inclusion => email_providers
end
In your form,
<%= f.select :email_provider,
options_for_select(Contact.email_providers, #contact.email_provider) %>
the second arg of the options_for_select will have any current email_provider selected.

Answer 9

I wanted to display one thing (human readable) but store another (an integer id).
Small example
Here's a small example that helped:
<%= form.select(:attribute_name, {cat: 5, dog: 3} )%>
The {cat: 5, dog: 3} will display "cat" and "dog", but save 5 and 3.
Real world example
Here's the actual use case. It displays the names of sellers (that humans can read), but saves the sellers' id (an integer):
<div class="field">
<%= form.label :seller_id %>
<%= form.select :seller_id, seller_names_and_ids(), {include_blank: true}, {required: true, class: "form-control"} %>
</div>
And the helper is defined as:
def seller_names_and_ids
# We want this to produce a hash of keys (the thing to display) and values (the thing to save,
# in thise case the seller_id integer)
sellers = Seller.all
h = {}
sellers.each do |seller|
thing_to_display = seller.name + " (" + seller.id.to_s + ")"
thing_to_save_in_db = seller.id
h.store(thing_to_display, thing_to_save_in_db)
end
h
end