Question

当我尝试更新我的页面对象时，我收到错误“未定义的方法`update_attributes'为nil：NilClass”。我在pry中确认@page是空的，但我不知道为什么？

def new
    @page = Page.new
    @subjects = Subject.order('position ASC')
    @page_count = Page.count + 1
  end

  def create
    @page = Page.new(page_params)
    if @page.save
      flash[:notice] = 'New page added!'
      redirect_to action: 'index'
    else
      @subjects = Subject.order('position ASC')
      @page_count = Page.count + 1
      render 'new'
    end
  end

  def edit
    @page = Page.find_by(id: params[:id])
    @subjects = Subject.order('position ASC')
    @page_count = Page.count
  end

  def update
    @page = Page.find_by(id: params[:id])
    if @page.update_attributes(page_params)
      flash[:notice] = 'Page has been updated!'
      redirect_to action: 'show', id: @page.id
    else
      @subjects = Subject.order('position ASC')
      @page_count = Page.count
      render 'edit'
    end
  end
     private

  def page_params
    params.require(:page).permit(:subject_id, :name, :permalink, :position, :visible)
  end

Routes:
match ':controller(/:action(/:id))', :via => [:get, :post]

Answer 1

确保params[:id]不是空白，您可以查看您的观看次数。然后您可以使用ID搜索，如果没有记录，则使用Object＆＃39; s #try方法：

@page = Page.find_by_id(params[:id])
if @page.try(:update_attributes, page_params)
...

未定义的方法`update_attributes＆＃39; for nil：更新对象时的NilClass

1 个答案: