未定义方法`build_book_reservation

Question

嗨，我只是想知道为什么会话在刷新时找不到我的预订，并在另一个控制器中使用它。

这是我的应用程序控制器

  helper :all # include all helpers, all the time


     private
 def current_reservation
   @reservation ||= Reservation.find(session[:reservation_id]) if session[:reservation_id]
   #last assigned value will be returned as default.
 end

 def create_reservation_session(id)
   session[:reservation_id] = id
 end

 def destroy_reservation_session
   session[:reservation_id] = nil
 end

我想让我们在这里

 def new
   @book_reservation = BookReservation.new
 end

def create
  @reservation = current_reservation
  @book_reservation=@reservation.build_book_reservation(params[:book_reservation])
  if @book_reservation.save
    #If success set session
    create_reservation_session(@reservation.id)
    #redirect_to root_url, :notice => "Successfully created book reservation."
  else
    render :action => 'new'
  end
 end

它引发undefined methodbuild_book_reservation‘以表示0:NilClass`’error

模型/书籍储备b

 belongs_to :reservation

模型/储备库

has_one :book_reservation

Answer 1

错误的原因是您从未设置会话，但尝试访问应用程序控制器使用的it.In。

private
 def current_reservation
   @reservation ||= Reservation.find(session[:reservation_id]) if session[:reservation_id]
   #last assigned value will be returned as default.
 end

 def create_reservation_session(id)
   session[:reservation_id] = id
 end

 def destroy_reservation_session
   session[:reservation_id] = nil
 end

在你的控制器里

 def new
   @book_reservation = BookReservation.new
 end

def create
  @reservation = Reservation.find(params[:reservation_id])
  if @reservation
    @book_reservation=@reservation.build_book_reservation(params[:book_reservation])
    if @book_reservation.save
      #If success set session
      create_reservation_session(@reservation.id)
      #redirect_to root_url, :notice => "Successfully created book reservation."
    else
      render :action => 'new'
    end
   else
      render :action => 'new'
   end

然后，无论何时需要，您都可以使用current_reservation。

Answer 2

您从来没有将:reservation_id放在会话中。

这意味着session[:reservation_id]是nil，Reservation.find(nil)引发了您正在看到的异常。