Error in rails 5 form on Create - ruby-on-rails

Question

I am new in rails and I'm trying to make a form to associate roles with users, I have two collection_select in the form but when I want to create or update I get this error:
my controller code is :
class UserRolesController < ApplicationController
before_action :set_user_role, only: [:show, :edit, :update, :destroy]
##roles =RolesController.new
##users =UsersController.new
# GET /user_roles
# GET /user_roles.json
def index
#user_roles = UserRole.all
end
# GET /user_roles/1
# GET /user_roles/1.json
def show
end
# GET /user_roles/new
def new
#user_role = UserRole.new
#users =##users.get_all_users
#roles =##roles.get_all_roles
end
# GET /user_roles/1/edit
def edit
#users =##users.get_all_users
#roles =##roles.get_all_roles
#user_roles =UserRole.find(params[:id])
#selected_role=#user_roles.role_id
#selected_user=#user_roles.user_id
end
# POST /user_roles
# POST /user_roles.json
def create
#user_role = UserRole.new(user_role_params)
respond_to do |format|
if #user_role.save
format.html { redirect_to #user_role, notice: 'User role was successfully created.' }
format.json { render :show, status: :created, location: #user_role }
else
format.html { render :new }
format.json { render json: #user_role.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /user_roles/1
# PATCH/PUT /user_roles/1.json
def update
respond_to do |format|
if #user_role.update(user_role_params)
format.html { redirect_to #user_role, notice: 'User role was successfully updated.' }
format.json { render :show, status: :ok, location: #user_role }
else
format.html { render :edit }
format.json { render json: #user_role.errors, status: :unprocessable_entity }
end
end
end
# DELETE /user_roles/1
# DELETE /user_roles/1.json
def destroy
#user_role.destroy
respond_to do |format|
format.html { redirect_to user_roles_url, notice: 'User role was successfully destroyed.' }
format.json { head :no_content }
end
end
def get_user_role_by_userid(user_id)
return UserRole.where(user_id:user_id).first
end
private
# Use callbacks to share common setup or constraints between actions.
def set_user_role
#user_role = UserRole.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def user_role_params
params.require(:user_role).permit(:role_id,:user_id)
end
end
My form code is :
<%= form_for(user_role) do |f| %>
<% if user_role.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(user_role.errors.count, "error") %> prohibited this user_role from being saved:</h2>
<ul>
<% user_role.errors.full_messages.each do |message| %>
<li><%= message %></li>
<% end %>
</ul>
</div>
<% end %>
<div class="field">
<%= f.label :user %>
<%= collection_select(:user_id, :user_id,#users, :id, :name,{:selected => #selected_user}) %>
</div>
<div class="field">
<%= f.label :rol %>
<%= collection_select(:role_id, :role_id,#roles, :id, :role {:selected => #selected_role}) %>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
What i am doing wrong? , how i have to set the user_role_params in this case?
I am using ruby 2.3.1 and Rails : 5.0.1
Thanks for your suggestions.

Answer 1

You need to put an f before collection set like this:
<%= form_for(user_role) do |f| %>
<% if user_role.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(user_role.errors.count, "error") %> prohibited this user_role from being saved:</h2>
<ul>
<% user_role.errors.full_messages.each do |message| %>
<li><%= message %></li>
<% end %>
</ul>
</div>
<% end %>
<div class="field">
<%= f.label :user %>
<%= f.collection_select(:user_id, #users, :id, :name,{:selected => #selected_user}) %>
</div>
<div class="field">
<%= f.label :rol %>
<%= f.collection_select(:role_id, #roles, :id, :role {:selected => #selected_role}) %>
</div>
<div class="actions">
<%= f.submit %>
</div>
otherwise the params are being sent like user_id instead of user_role[user_id]