Question

我正在使用Rails构建一个简单的博客应用程序，并且我尝试创建为帖子提交评论的功能。但是，我一直收到此错误

表单中的第一个参数不能包含nil或为空

<h3> Submit a Comment </h3>

<%= form_for [@post, @comment] do |c| %> 
//Error is here, @comment appears to be nil and I'm not sure why 
//(I've checked both cases)

  <%= c.label :body, "Comment: " %>
  <br />
  <%= c.text_area :body %>

我已检查过其他有类似问题但无法找到解决方案的帖子。任何帮助将不胜感激

class CommentsController < ApplicationController

  def create
    @post = Post.find params[:post_id]

    comment_params = params.require(:comment).permit(:body)

    @comment = Comment.new comment_params
    @comment.post = @post
    # Why is my comment nil?

    if @comment.save
      redirect_to post_path(@post), notice: "Comment successful"
    else
      flash[:alert] = "Comment unsuccessful. Please do not enter an empty comment"
      render "/posts/show"
    end

  end

  def destroy
    # To be implemented
  end

end

编辑：解决了，忘了在我的Post控制器的show方法中添加@comment = Comment.new

谢谢大家！

Answer 1

您正在创建新评论。你应该：

一个。在控制器的某个地方@comment = Comment.new

OR

B中。然后用

实例化它

form_for [@post, Comment.new] do |c| #...

form_for在具有已定义关联的Rails中的第一个参数nil错误

1 个答案: