下拉列表未显示rails

Question

I have a dropdown list that is supposed to show all the users in the db. The dropdown is showing but the contents of the dropdown are not.

I'm getting the content from the MessagesHelper which is:

module MessagesHelper
 def recipients_options(chosen_recipient = nil)
   s = ''
   User.all.each do |user|
    s << "<option value='#{user.id}' #{'selected' if user == chosen_recipient}>#{user.username}</option>"
   end

   s.html_safe
  end
end

And I render it using this code:

<%= select_tag 'recipients', recipients_options(@chosen_recipient), class: 'form-control chosen-it' %>

Anyone seeing what I'm missing out on? I'll really appreciate the help.

Answer 1

You should really be using options_from_collection_for_select for this.

This, to quote the docs:

Returns a string of option tags that have been compiled by iterating over the collection and assigning the result of a call to the value_method as the option value and the text_method as the option text.

That way, you can simply use:

<%= select_tag 'recipients', options_from_collection_for_select(User.all, :id, :username, @chosen_recipient.id), class: 'form-control chosen-it' %>

This is a built in helper designed to do what you're recreating, so will work perfectly.

The arguments are the collection to build options from, the method to call for the value, the method for the options' text and the selected value.

Hope that helps - let me know how you get on or if you have any questions.