ROR application - pass data from view to controller - ruby-on-rails

Question

Trying to pass data from a view to controller using Javascript. How do I do this ? Specifically the information I wish to access in the controller is what option/s have been selected in a variable number (one to many) of selections on the screen.
I have a ROR application I am developing and on the "Companies - Drill Interests" screen I wish to use java/coffeescript to send data and invoke controller action. In the controller I can't get access to all the data I need to respond. That is I can' determine what "Saved Assumption" the user has selected.
From the Companies controller building array (should I be doing this or using another method) of saved assumptions.
def companies_drill_interests
# intial display use first (if present) user drill evaluations
#result_list = Array.new
#company_listings.each do |cl|
#drill_interests.each do |di|
target_share_price = 0
result = Hash.new
result["cl_display_name"] = cl.display_name
result["di"] = di.drill.name
result["target_share_price"] = 0
# if saved assumptions grab first assumption and then first target_share_price
#matched_evaluation_assumption =
EvaluationAssumption.matched_eval_assum(#current_user.id, di.drill_id)
...
# code that builds result ...
end
end
#result_list << result
end
end
end
from the screen partial views/companies/_companies_drill_interests
<%= simple_form_for #company,
html: { class: 'infogroup',
id: "x_company_drill_interests"} do |f| %>
<div class="infogroup-header">Drill Interests</div>
<div class="infogroup-body">
<table border="0" cellpadding="0" cellspacing="0" class="info">
<th class="very_large_column lalign">Drill Name</th>
...
<% if #drill_interests.present? %>
<% index = 0 %>
<% #drill_interests.each do |drill_interest| %>
<%= fields_for "drill_interest[]", drill_interest do |di| %>
<tr>
<td><%= drill_interest.drill.name %></td>
<td class="ralign"><%= drill_interest.equity_percentage %></td>
<% array_name = "evaluation_assumption" + index.to_s %>
<td id="x_user_eval_assum" class='lalign large_column' data-targets="<%= #probability_json %>">
<td> <%= select("mea_user_save_name", "id",
#assumptions[array_name].collect {|r| [ r["mea_user_save_name"], r["id"] ] },
{ :include_blank => false }) %> </td>
<% index += 1 %>
</tr>
<% end %>
...
If the user changes the "Saved Asumptions" selection this is detected in jave/coffeescript. From app/assets/javascript/companies.js.coffee
...
$('#x_company_drill_interests').change((event) ->
company_id = $('.form.companies_drill_interests').attr('data-companyid')
event.preventDefault()
calculateResult company_id
)
calculateResult = (company_id)->
data = $('#x_company_drill_interests').serialize()
$.ajax
url:"/companies/#{company_id}/projection.json",
type:"post"
...
Display statement in Companies Controller for when the action I can't get to work is performed.
class CompaniesController < ApplicationController
...
def projection
puts "================================="
puts "params = " + params.to_s
puts "================================="
...
In the logs output from this statement
params = {"utf8"=>"✓", "_method"=>"patch", "authenticity_token"=>"rFx8TBWnECUCxFiEBQ+0lTmkvhUKEJrUx/SlEQNPEP8=", "mea_user_save_name"=>{"id"=>""}, "action"=>"projection", "controller"=>"companies", "id"=>"18", "format"=>"json"}. The arrays are not present.
Overview of relationships between models.
Company has 0 to many drill_Interests. Each Drill_interest has 0 to many Evaluation_Assumptions (and using Evaluation_Assumptions I wish to display User_Evaluation_Results).
If you wish to see above you can visit the application as per instructions below.
1- go to http://quiet-fortress-3338.herokuapp.com/users/login
2- login with userid = pmlc and password = gmfive99
3- select companies from menu top RHS
4- select ADO
5- Select screen "Companies Drill Interests"
You will see ADO has an interest in both "Temp-01" and "ZZZ-Unlimited" with a number of saved assumptions for both

Answer 1

You are using fields_for, so change:
<td> <%= select("mea_user_save_name", "id",
#assumptions[array_name].collect {|r| [ r["mea_user_save_name"], r["id"] ] },
{ :include_blank => false }) %> </td>
to
<td> <%= di.select("mea_user_save_name", "id",
#assumptions[array_name].collect {|r| [ r["mea_user_save_name"], r["id"] ] },
{ :include_blank => false }) %> </td>

Answer 2

Try to use select_tag instead of select

Answer 3

select_tag statement
select_tag "whatever_name", options_from_collection_for_select(#assumptions[array_name].collect {|r| [ r["mea_user_save_name"], r["id"] ] }, "id", "mea_user_save_name"), include_blank: true

Answer 4

To send and array to backend using fields the fields must be named
<input name="myfieldarray[]">
In this way form.serialize() sends an array for myfieldarray.
check this question
How to pass an array from view to controller in Ruby on Rails
try this.
select_tag "my_array_param[]", options_from_collection_for_select(#assumptions[array_name].collect {|r| [ r["mea_user_save_name"], r["id"] ] }, "id", "mea_user_save_name"), include_blank: true