在控制器更新操作上处理 collection_select

Question

我有 2 个模型

第一个模型 category.rb

class Category
  include Mongoid::Document

 # Relationships
  has_many :boards, :dependent => :destroy , :autosave => true
  accepts_nested_attributes_for :boards

  #fields
  field :name

  #attr
  attr_accessible :name, :boards_attributes
end

第二个模型是 board.rb

class Board
 include Mongoid::Document

#Relationships
 belongs_to :category

  #fields
  field :name
  field :description

  #attr
  attr_accessible :name, :description

end

一个形式：

<%= form_for [@board], :url => user_board_path do |f| %>
 <%= f.text_field :name %>
 <%= f.text_area :description, :cols =>72, :rows => 5, %>
 <%= f.collection_select :category_id, Category.all, :id, :name%>
<% end %>

我在 编辑板视图 中有下 来自boards_controller.rb的更新操作有下一个：

def update
  @board = Board.find(params[:id])
  @category = Category.find(params[:category_id])
  @board.category_id = @category

 respond_to do |format|
   if @board.update_attributes(params[:board])
     format.html { redirect_to user_board_path(@board.user, @board), notice: 'Board was successfully updated.' }
     format.json { head :ok }
   else
     format.html { render action: "edit" }
     format.json { render json: @board.errors, status: :unprocessable_entity }
   end
 end
end

为什么我得到@board.category_id nil？我想用我在 select 中选择的值更新 @board.category_id

Answer 1

问题是 @board.category_id = @category （您将对象设置为 id 字段）。应该是

@board = Board.find(params[:id])
@category = Category.find(params[:category_id])
@board.category = @category

，或者如果 @category 未在控制器或视图中使用，您可以编写

@board = Board.find(params[:id])
@board.category_id = params[:category_id]

第二个解决方案删除类别上的“SELECT”请求