Question

我在使用scaffold

的教程中发现了这个问题

undefined method `save' for nil:NilClass

我不知道为什么会这样，因为我没有改变任何东西，当我生成Comment类时，这个方法会由脚手架自动编写。发生了什么？我是业余爱好者，所以我不知道在这里展示什么代码。非常感谢你的帮助。

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

  def create
    @link = Link.find(params[:link_id])
    @comment = @link.comments.new[comment_params]
    @comment.try[:user] = current_user

    respond_to do |format|
      if @comment.save
        format.html { redirect_to @link, notice: 'Comment was successfully created.' }
        format.json { render json: @comment, status: :created, location: @comment }
      else
        format.html { render action: "new" }
        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(:link_id, :body, :user_id)
    end
end

Answer 1

未定义的方法`save'代表nil：NilClass

我认为错误是由于以下行

@comment = @link.comments.new[comment_params]

应该是

@comment = @link.comments.new(comment_params)

未定义的类由脚手架轨道制成

1 个答案: