AssociationTypeMismatch in ItemsController#create - ruby-on-rails

Question

Im creating an online retail store. That has Items that are belongs_to a category. When i try to submit the item with a category selected it wont save
I tried for many hours to fix but can't figure it out. Anyone see what the problem is?
Error is
ActiveRecord::AssociationTypeMismatch in ItemsController#create
Category(#70298375791060) expected, got String(#70298372605800)
def create
#item = current_user.items.build(item_params)
if #item.save
redirect_to #item
flash[:success] = "You have created a new item"
Items Form
<h1>Create New item</h1>
<div class="container">
<div class=“row”>
<div class="col-md-6 col-md-offset-3">
<div class="panel panel-primary">
<div class="panel-body">
<%= simple_form_for #item, html: { multipart: true } do |f| %>
<%= f.input :image%>
<%= f.collection_select :category, Category.order(:name), :id, :name, include_blank: true, :prompt => "Select One Category" %>
<%= f.input :title%>
<%= f.input :price %>
<%= f.input :description %>
<%= f.button :submit, "Create new item", class: "btn btn-primary" %>
<% end %>
</div>
</div>
</div>
</div>
</div>
Items Controller
class ItemsController < ApplicationController
before_action :correct_user_edit, only: [:edit, :update, :destroy]
def index
#item = #user.items.paginate(page: params[:page])
end
def new
#item = Item.new
end
def home
#items = Item.paginate(page: params[:page])
end
def edit
#item = Item.find(params[:id])
#user = User.find(params[:id])
end
def show
#item = Item.find(params[:id])
end
def update
#item = Item.find(params[:id])
if #item.update(item_params)
redirect_to #item
flash[:success] = 'Item was successfully updated.'
else
render "edit"
end
end
def create
#item = current_user.items.build(item_params)
if #item.save
redirect_to #item
flash[:success] = "You have created a new item"
else
flash[:danger] = "Your item didn't save"
render "new"
end
end
def destroy
Item.find(params[:id]).destroy
flash[:success] = "Item deleted"
redirect_to users_url
end
private
def item_params
params.require(:item).permit(:title, :category, :price, :description, :image)
end
#Check to see if user can edit item.
def correct_user_edit
if #item = current_user.items.find_by(id: params[:id])
else
flash[:danger] = "You can't edit that item"
redirect_to root_url if #item.nil?
end
end
end
Item model
class Item < ActiveRecord::Base
belongs_to :user
belongs_to :category
validates :category, presence: true
validates :title, presence: true, length: { maximum: 30 }
validates :price, presence: true
validates :description, presence: true, length: { maximum: 2000 }
validates :user_id, presence: true
has_attached_file :image, styles: { large: "600x600", medium: "250x250", thumb:"100x100#"}
validates_attachment_content_type :image, content_type: /\Aimage\/.*\Z/
end
Category Model
class Category < ActiveRecord::Base
has_ancestry
has_many :items
end

Answer 1

ActiveRecord::AssociationTypeMismatch in ItemsController#create
Category(#70298375791060) expected, got String(#70298372605800)
This line
<%= f.collection_select :category, Category.order(:name), :id, :name, include_blank: true, :prompt => "Select One Category" %>
should be
<%= f.collection_select :category_id, Category.order(:name), :id, :name, include_blank: true, :prompt => "Select One Category" %>
And also change in the the item_params as well
def item_params
params.require(:item).permit(:title, :category_id, :price, :description, :image)
end
undefined method `category_id' for Item:0x007fdf43bebed0
You should have category_id column in items table. Run the following command which creates a migration file for adding category_id to items.
rails g migration add_category_id_to_items category_id:integer
and run rake db:migrate
And I suggest you to read these Guides before going further.

Answer 2

Instead of category, you should pass category_id param.