Ruby on rails NilClass:Class的未定义方法“model_name”

我试图允许用户对指南进行评论。错误发生在以下代码的第一行。这是评论表的一部分：

      <%= simple_form_for(@comment) do |f| %>
  <%= f.error_notification %>

  <div class="form-inputs">
    <%= f.input :body %>
    <%= f.hidden_field :guide %>
    <%= f.hidden_field :user %>
  </div>

  <div class="form-actions">
    <%= f.button :submit %>
  </div>
<% end %>

以下是整个控制器的注释：

class CommentsController < ApplicationController
  before_action :set_comment, only: [:show, :edit, :update, :destroy]

  # GET /comments
  # GET /comments.json
  def index
    @comments = Comment.all
  end

  # GET /comments/1
  # GET /comments/1.json
  def show
  end

  # GET /comments/new
  def new
    @comment = Comment.new
  end

  # GET /comments/1/edit
  def edit
  end

  # POST /comments
  # POST /comments.json
  def create
    @comment = Comment.new(comment_params)

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

  # PATCH/PUT /comments/1
  # PATCH/PUT /comments/1.json
  def update
    respond_to do |format|
      if @comment.update(comment_params)
        format.html { redirect_to @comment, notice: 'Comment was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: 'edit' }
        format.json { render json: @comment.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /comments/1
  # DELETE /comments/1.json
  def destroy
    @comment.destroy
    respond_to do |format|
      format.html { redirect_to comments_url }
      format.json { head :no_content }
    end
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_comment
      @comment = Comment.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def comment_params
      params.require(:comment).permit(:body, :guide_id, :user_id)
    end
end

---

如何正确显示注释？

您的代码中有错误。您发布了一个

CommentsController

，但您的错误清楚地表明调用的视图是一个

guides

视图（应该属于GuidesController）

而且这些路线只包括一个

：指南
资源，而不包括注释。从不使用注释控制器

如果要将编辑指向该控制器，则需要关联一个路由。
发布处理该操作的控制器的代码。如果问题是引发的异常，则始终从log@SimoneCarletti-完成。您可以发布呈现此部分的视图吗？路由确实包括：注释资源，但是格式问题意味着它没有显示在代码块-fixed中，但这似乎不是调用的路由。如果您检查控制台，它可能会告诉您处理请求的控制器。我需要做什么来修复此问题？你们还需要什么进一步的信息来帮助？我想@SimoneCarletti得到的是
指南控制器
处理了这个请求，而不是
注释控制器
，因此
@comment
从未设置过。您需要检查路由与请求的URI，以验证这一点。
Runescapeguides::Application.routes.draw do
  resources :comments

  devise_for :users

  resources :guides do
    member do
      put "like", to: "guides#upvote"
      put "dislike", to: "guides#downvote"
    end
  end
end

class CommentsController < ApplicationController
  before_action :set_comment, only: [:show, :edit, :update, :destroy]

  # GET /comments
  # GET /comments.json
  def index
    @comments = Comment.all
  end

  # GET /comments/1
  # GET /comments/1.json
  def show
  end

  # GET /comments/new
  def new
    @comment = Comment.new
  end

  # GET /comments/1/edit
  def edit
  end

  # POST /comments
  # POST /comments.json
  def create
    @comment = Comment.new(comment_params)

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

  # PATCH/PUT /comments/1
  # PATCH/PUT /comments/1.json
  def update
    respond_to do |format|
      if @comment.update(comment_params)
        format.html { redirect_to @comment, notice: 'Comment was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: 'edit' }
        format.json { render json: @comment.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /comments/1
  # DELETE /comments/1.json
  def destroy
    @comment.destroy
    respond_to do |format|
      format.html { redirect_to comments_url }
      format.json { head :no_content }
    end
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_comment
      @comment = Comment.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def comment_params
      params.require(:comment).permit(:body, :guide_id, :user_id)
    end
end

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app/views/guides/show.html.erb:29:in `_app_views_guides_show_html_erb___4114194112307075162_2193467420'