0的未定义方法“`projects”：NilClass

Question

是我的项目类是nill还是什么，谁能解释我这个错误。

NoMethodError (未定义方法projects' for nil:NilClass): ) app/controllers/project_controller.rb:8:in指数‘ 呈现/Users/ajaysithagari/.rvm/gems/ruby-2.2.1/gems/actionpack-4.2.3/lib/action_dispatch/middleware/templates/rescues/_source.erb (6.2ms)呈现/Users/ajaysithagari/.rvm/gems/ruby-2.2.1/gems/actionpack-4.2.3/lib/action_dispatch/middleware/templates/rescues/_trace.html.erb (3.4ms)呈现/Users/ajaysithagari/..rvm/gems/ruby-2.2.1/gems/actionpack-4.2.3/lib/action_dispatch/middleware/templates/rescues/_request_and_response.html.erb (1.0ms)在救援/布局(50.0ms)中呈现/用户/ajaysithagari/..rvm/gems/ruby-2中的/Users/ajaysithagari/.rvm/gems/ruby-2.2.1/gems/actionpack-4.2.3/lib/action_dispatch/middleware/templates/rescues/diagnostics.html.erb。2.1/gems/web-console-2.2.1/lib/web_console/templates/_markup.html.erb (0.4ms)在布局中呈现/Users/ajaysithagari/.rvm/gems/ruby-2.2.1/gems/web-console-2.2.1/lib/web_console/templates/_inner_console_markup.html.erb /内联字符串(0.3ms)呈现/用户/ajaysithagari/..rvm/gems/ruby2.2.1/布局中的gems/web-console-2.2.1/lib/web_console/templates/_prompt_box_markup.html.erb /内联_string (0.3ms)在布局中呈现/Users/ajaysithagari/.rvm/gems/ruby-2.2.1/gems/web-console-2.2.1/lib/web_console/templates/style.css.erb /内联_string (0.4ms)呈现/User/ajaysithagari/..rvm/gems/ruby2.2.1布局中的/gems/web-console-2.2.1/lib/web_console/templates/console.js.erb /javascript (41.3ms)在布局中呈现/Users/ajaysithagari/.rvm/gems/ruby-2.2.1/gems/web-console-2.2.1/lib/web_console/templates/main.js.erb /javascript (0.3ms)呈现/Users/ajaysithagari/.rvm/gems/ruby-2.2.1/gems/web-console-2.布局中的2.1/lib/web_console/templates/error_page.js.erb /javascript (0.4ms)呈现为/Users/ajaysithagari/.rvm/gems/ruby-2.2.1/gems/web-console-2.2.1/lib/web_console/templates/index.html.erb (93.4ms)

这是我的项目负责人

before_action :confirm_logged_in

  before_action :find_company


  def index

    @projects = @company.projects.sorted
  end

  def show

    @project = Project.find(params[:id])
  end

  def new

    @project = Project.new()
  end

  def create

    @project = Project.new(project_params)
    if @project.save
      redirect_to(:action => 'index')
    else
      render('new')
    end
  end

  def edit

    @project = Project.find(params[:id])
  end

  def update

    @project = Project.find(params[:id])
    if @project.update_attributes(project_params)
      redirect_to(:action => 'index')
    else
      render('new')
    end
  end

  def delete

    @project = Project.find(params[:id])
  end

  def destory

    @project = Project.find(params[:id])
    @project.destroy
    redirect_to(:action => 'index')
  end


  private 

  def project_params

   params.require(:project).permit(:name, :position, :type_of_project, :description, :no_of_tasks)
  end

  def find_company

    if params[:company_id]
      @company = Company.find(params[:company_id])
    end
  end
end

实际上，在进入项目之前，我们需要找到company_id，索引@projects = @company.projects.sorted意味着公司有很多项目。

Answer 1

问题在于if params在def find_company中。对于index函数，没有设置它。

将def索引更改为：

def index
  @projects = Project.sorted
end

更新:犯了错误，我想：

def index
  @projects = Project.all.sorted #or leave the call to sorted out completely
end