控制器

Question

首先，我已经找到了一些非常有用的答案（见下面的链接），但我仍然在努力使这项工作成功。我已经很长时间没有编程了，这肯定会让我觉得自己感觉很舒服。

我有三个型号。例如，我将它们称为Tree，Bark，Engraving（评论）。我试图为用户添加一个简单的表单，以便用户提交新的评论（版画）。

以下设置产生错误：

/ trees / 1处的NoMethodError 未定义的方法`tree＆＃39;为零：NilClass

控制器

class TreesController < ApplicationController
  def show
   @barks = Bark.where(tree_id: @tree.id)
   @engraving= Engraving.new( :bark=> @bark)  
  end
end

class BarksController < ApplicationController
  def show
   @engravin= Engraving.new( :bark=> @bark)
   @engravings = Engraving.where(bark_id: @bark.id)  
  end
end

class EngravingsController < ApplicationController
  def show
   @bark= Bark.find(params[:bark_id])
   @engraving = Engraving.new(params[:engraving])  
  end
end

def create
@bark = Bark.find(params[:bark_id])
@engraving = Engraving.new(params[:engraving])
@engraving.user_id = current_user.id


respond_to do |format|
  if @engraving.save
    format.html { redirect_to tree_bark_path(@tree, @bark), notice: 'Comment was       successfully created.' }
    format.json { render action: 'show', status: :created, location: @engraving}
  else
    format.html { render action: 'new' }
    format.json { render json: @engraving.errors, status: :unprocessable_entity }
  end
end

端

模型

class Tree < ActiveRecord::Base
  belongs_to :user
  has_many :barks
  has_many :engravings, through: :barks
end

class Bark< ActiveRecord::Base
  belongs_to :user
  belongs_to :tree
  has_many :engravings

  delegate :title, :link, :to => :tree, :prefix => true

  def new_engraving_path
    Rails.application.routes.url_helpers.new_tree_bark_engraving_path(book, self)
  end

  def serializable_hash(*args)
    super.merge 'new_engraving_path' => new_engraving_path
  end
end

class Engraving< ActiveRecord::Base
  belongs_to :user
  belongs_to :bark

  delegate :tree, :to => :bark, :prefix => true

  def to_edit_path
    Rails.application.routes.url_helpers.edit_tree_bark_engraving_path bark_tree, bark, self
  end

  def to_path
    Rails.application.routes.url_helpers.tree_bark_engraving_path bark_tree, bark, self
  end

  def serializable_hash(*args)
    super.merge 'path' => to_path, 'edit_path' => to_edit_path
  end
end

在视图中调用表单

在树秀页面上，我有所有的树皮在那里填充。单击Bark元素将打开一个模态，其中显示Bark.content和Engravings。在最后的Engraving中，我希望有一个text_area表单来创建一个新的Engraving，并将其添加到这个＆＃34; piece＆＃34;树皮。

# trees\show.html.erb
<%= render @barks %>

# barks\_bark.html.erb
<%= render partial: 'barks/modal', locals: { bark: bark} %>

# barks\modal.html.erb
<% render partial: '/engravings/simpleForm', :collection => bark.engravings %>

# Form partial

  <%= form_for @engraving, :url => (new_tree_bark_engraving_path(:tree_id => @bark.tree, :bark_id => @bark.id)) do |f| %>
    <%= f.hidden_field :bark_id %> 

     <div class="field">
      <%= f.text_area :content %>
     </div>

     <div class="actions">
      <%= f.submit %>
     </div>
  <% end %>

路线

    get "pages/home"

    resources :trees do
      collection do
        get 'search'
        post 'load_from_api'
      end
    resources :barks do
      resources :engravings
    end
  end
    resources :barks do
      resources :engravings
    end

  root "trees#index"

其他答案来源

Rails Routing Error for nested form_for

Twice Nested Resource Form_For Issue

form_for with nested resources

Answer 1

您的错误消息NoMethodError at /trees/1 undefined method 'tree' for nil:NilClass表示您必须在某个.tree对象上调用nil。我能看到的唯一地方是部分形式。我假设@bark.tree失败了。

根据您的问题，您不清楚从哪个控制器呈现部分控件，但最可能的原因是@bark未传递到表单中。确保您将@bark传递给您的部分，这是一个示例：

<%= render partial: "form", locals: {bark: @bark} %>

Answer 2

您在@barks中确定trees#show action，但绝不会@bark

def show @barks = Bark.where(tree_id: @tree.id) @engraving= Engraving.new( :bark=> @bark) end

所以@bark是零。

Rails 4 form_for双嵌套注释

控制器

模型

在视图中调用表单

路线

其他答案来源

2 个答案: