Rails部分集合未呈现

Question

I am following a tutorial and we are creating a partial to to display a collection of data, but it is not rendering, my rails server command prompt shows that the database transaction is succesful:

Started GET "/portfolios" for ::1 at 2019-05-09 11:52:03 -0500
Processing by PortfoliosController#index as HTML
  Rendering portfolios/index.html.erb within layouts/portfolio
  Portfolio Load (0.3ms)  SELECT "portfolios".* FROM "portfolios"
  ↳ app/views/portfolios/index.html.erb:5
  Rendered collection of portfolios/_portfolio_item.html.erb [11 times] (2.1ms)
  Rendered portfolios/index.html.erb within layouts/portfolio (5.3ms)
  Rendered shared/_nav.html.erb (0.8ms)
Completed 200 OK in 31ms (Views: 28.6ms | ActiveRecord: 0.3ms)

Here is my partial under portfolios/_portfolio_item.html.erb:

<p><%= link_to portfolio_item.title, portfolio_show_path(portfolio_item) %></p>

<p><%= portfolio_item.subtitle %></p>

<p><%= portfolio_item.body %></p>

<%= image_tag portfolio_item.thumb_image unless portfolio_item.thumb_image.nil? %>
<%= link_to "Edit", edit_portfolio_path(portfolio_item) %>
<%= link_to 'Delete Portfolio Item', portfolio_path(portfolio_item), method: :delete, data: { confirm: 'Are you sure?' } %>

My index view under portfolios/index.html.erb :

<h1>Portfolio Items</h1>

<%= link_to "Create New Item", new_portfolio_url %>

<%= render partial: 'portfolio_item', collection: @portfolio_items %>

And my portfolios_controller :

class PortfoliosController < ApplicationController
  layout 'portfolio'

  def index
    @portfolio_items = Portfolio.all
  end

  def show
    @portfolio_item = Portfolio.find(params[:id])
  end

  def new
    @portfolio_item = Portfolio.new
    3.times { @portfolio_item.technologies.build }
  end

  def create
    @portfolio_item = Portfolio.new(portfolio_params)

    respond_to do |format|
      if @portfolio_item.save
        format.html { redirect_to portfolios_path, notice: 'Your portfolio item is now live!' }
      else
        format.html { render :new }
      end
    end
  end

  def edit
    @portfolio_item = Portfolio.find(params[:id])
  end

  def update
    @portfolio_item = Portfolio.find(params[:id])
    respond_to do |format|
      if @portfolio_item.update(portfolio_params)
        format.html { redirect_to portfolios_path, notice: 'The record was successfully updated.' }
      else
        format.html { render :edit }
      end
    end
  end

  def destroy
    @portfolio_item = Portfolio.find(params[:id])
    @portfolio_item.destroy
        respond_to do |format|
      format.html { redirect_to portfolios_url, notice: 'Portfolio was successfully destroyed.' }
    end
  end

  private

  def portfolio_params
    params.require(:portfolio).permit(:title,
                                      :subtitle,
                                      :body,
                                      :main_image,
                                      :thumb_image,
                                      technologies_attributes: [:name])
  end
end

If there is anything further needed please let me know and thanks in advance!

Answer 1

I'm not familiar with the collection syntax bbut for a quick fix try:

## index.html.erb

<h1>Portfolio Items</h1>

<%= link_to "Create New Item", new_portfolio_url %>

<% @portfolio_items.each do |item| %>
  <%= render partial: 'portfolio_item', portfolio_item: item %>
<% end %>

Or if you really want to be fancy, and your model is called Portfolio, rename your partial to portfolios/_portfolio.html.erb . That will let you do:

## index.html.erb

<h1>Portfolio Items</h1>

<%= link_to "Create New Item", new_portfolio_url %>

<% @portfolio_items.each do |item| %>
  <%= render item %>
<% end %>

Answer 2

Make sure there is no CSS or javascript that is removing/hiding your views. Also make sure you actually have some instances(rows) of the portfolio in your database.

<%= render partial: 'portfolio_item', collection: @portfolio_items %>

Although your usage of collection in partial is correct you can try to pass local variables and see if it works, because collection usage is dependent on file/model names which could cause issues.

When you use collection: @portfolio_items then you get access to use @portfolio_items instance variable within the partial view ( portfolios/_portfolio_item.html.erb in your case). You are passing @portfolio_items but not using it anywhere, instead you are using portfolio_item variable which is not available in the partial view.

You need to iterate over @portfolio_items in order to render your items. If you need to pass variables to your partial use locals . Update your portfolios/index.html.erb as below

<h1>Portfolio Items</h1>

<%= link_to "Create New Item", new_portfolio_url %>

<% @portfolio_items.each do |portfolio_item| %>
    <%= render partial: 'portfolio_item', locals: { portfolio_item: portfolio_item } %>
<% end %>