CommentsController 中的 NoMethodError #new undefined method `text' for #<Comment id: nil, author: nil, created_at: nil, updated_at: nil>

Question

我正在尝试将 Rails 与 React 一起使用，只需将 cmets 部分添加到我正在开发的应用程序中即可。 /comments 页面有效。但是当我尝试发表新评论时。我得到这个错误。我回到了我正在使用的指南，并没有对此做出任何解释。我是 Rails 的新手并且会做出反应，所以如果有人可以帮助我，我将不胜感激。

应用程序跟踪：

app/views/comments/_form.html.erb:20:in `block in_app_views_comments__form_html_erb__930297241_104622300'
app/views/comments/_form.html.erb:1:in `_app_views_comments__form_html_erb__930297241_104622300'
app/views/comments/new.html.erb:3:in `_app_views_comments_new_html_erb__151456299_104688260'

cmets_controller.rb:

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 :show, status: :created, location: @comment }
            else
                format.html { render :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 { render :show, status: :ok, location: @comment }
            else
                format.html { render :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, notice: 'Comment was successfully destroyed.' }
        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(:author, :comment_text)
        end
end

_form.html.erb：

<%= form_for(@comment) do |f| %>
<% if @comment.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(@comment.errors.count, "error") %> prohibited this comment from being saved:</h2>

<ul>
    <% @comment.errors.full_messages.each do |message| %>
        <li><%= message %></li>
    <% end %>
</ul>
</div>
<% end %>

<div class="field">
    <%= f.label :author %><br>
    <%= f.text_field :author %>
</div>
<div class="field">
    <%= f.label :comment_text %><br>
    <%= f.text_area :comment_text %>
</div>
<div class="actions">
    <%= f.submit %>
</div>
<% end %>

new.html.erb：

<h1>New Comment</h1>

<%= render 'form' %>

<%= link_to 'Back', comments_path %> 

[时间戳]_create_cmets.rb:

class CreateComments < ActiveRecord::Migration
    def change
        create_table :comments do |t|
            t.string :author
            t.text :comment_text

            t.timestamps null: false
        end
    end
end 

Answer 1

似乎问题源于您的架构/迁移。行：

params.require(:comment).permit(:author, :text)

建议您有一个名为 text 的列，它是 Rails 中的一种数据类型。您应该为该列选择一个不回显数据类型名称的名称，例如“comment_text”。

您也可能在迁移中转置了数据类型和列名。