ruby-on-rails - 如何在关联模型只有一个实例时隐藏表单 #rails #beginner

Question

我正在尝试创建一个类似系统的评论，用户可以在其中向“决定”添加“结果”。当决策中添加了 1 个时，我喜欢隐藏结果创建表单以“隐藏”。

我最好的猜测是计算结果与决策相关联的实例的数量，并创建一个 if 语句以在结果实例超过 0 时隐藏表单。

我尝试了不同的方法来完成这个，但我似乎无法使计数或 if 语句起作用。我是编码新手，供您引用:-)。

谁能给我建议如何解决这个问题？

我的代码: Controller /decisions_controller.rb

class DecisionsController < ApplicationController
before_action :find_decision, only: [:show, :edit, :update, :destroy]

  def index
# gets all rows from decision table and puts it in @decision variable
    @decisions = Decision.all
  end

  def show
# find only the decision entry that has the id defined in params[:id]
  end
# shows the form for creating a entry
  def new
    @decision = Decision.new
  end
# creates the entry
  def create
    @decision = Decision.new(decision_params)
      if @decision.save
        redirect_to @decision
      else
        render 'new'
      end
  end
# shows the form for editing a entry
  def edit
  end
# updates the entry
  def update
    if @decision.update(decision_params)
      redirect_to @decision
    else
      render 'edit'
    end
  end

  def destroy
    @decision.destroy
    redirect_to root_path
  end

  private
  def find_decision
# Loads the right entry.
      @decision = Decision.find(params["id"])
  end

  def decision_params
    params.require(:decision).permit(:title, :forecast, :review_date)
  end

end

Controller /outcomes_controller.rb

class OutcomesController < ApplicationController
    def create
        @decision = Decision.find(params[:decision_id])
        @outcome = @decision.outcomes.create(params[:outcome].permit(:actual, :strength, :weakness))
          redirect_to decision_path(@decision)
    end
end

模型/结果.rb

class Outcome < ActiveRecord::Base
  belongs_to :decision
end

模型/决策.rb

class Decision < ActiveRecord::Base
  has_many :outcomes
end

决定/show.html.erb

    <h1>Decision showpage</h1>

<h2><%= @decision.title %></h2>
<p><%= @decision.created_at %></p>
<p><%= @decision.forecast %></p>
<p><%= @decision.review_date %></p>

<%= render @decision.outcomes %>


<%= link_to "Delete Decision", decision_path(@decision), method: :delete, data: { confirm: "Are you sure?" } %>

<%= render "outcomes/form" %>
<%= render "outcomes/outcome" %>

结果/_form.html.erb

<%= form_for([@decision, @decision.outcomes.build]) do |f| %>
  <%= f.label :actual %>:
  <%= f.text_field :actual %> <br/>

  <%= f.label :strength %>:
  <%= f.text_area :strength %> <br/>

  <%= f.label :weakness %>:
  <%= f.text_area :weakness %> <br/>
  <%= f.submit %>
  <% end %>

结果/_outcome.html.erb

<h2>outcome</h2>
<%= @decision.outcomes.first.actual %> </br>
<h3>What i found i'm good at</h3>
<%= @decision.outcomes.first.strength %> </br>
<h3>What i found i'm weak at</h3>
<%= @decision.outcomes.first.weakness %>

Answer 1

<h1>Decision showpage</h1>
<h2><%= @decision.title %></h2>
<p><%= @decision.created_at %></p>
<p><%= @decision.forecast %></p>
<p><%= @decision.review_date %></p>

<%= render @decision.outcomes %>


<%= link_to "Delete Decision", decision_path(@decision), method: :delete, data: { confirm: "Are you sure?" } %>
<%if @decision.outcomes.length < 1 %>
    <%= render "outcomes/form" %>
<%end%>
<%= render "outcomes/outcome" %>