Rails fields_for 不工作

Question

我正在尝试使用fields_for 并创建一个嵌套表单，但是只显示一个文本字段，空白。我有 3 个 crewmember 记录。

crewmember模特：

class Crewmember < ActiveRecord::Base
belongs_to :production
belongs_to :callsheet

validates :firstname, presence: true
validates :email, presence: true

def name
    "#{firstname} #{lastname}"
end

end

callsheet型号

class Callsheet < ActiveRecord::Base
attr_accessible :crewmembers_params
has_many :castmembers
has_many :crewmembers

accepts_nested_attributes_for :crewmembers
end

callsheets控制器

class CallsheetsController < ApplicationController
    def index
        @callsheets = Callsheet.all
        @departments = Department.where(production_id: current_user.default_working_production_id)
    end

    def show
        @callsheet = Callsheet.find(params[:id])
    end

    def new
        @callsheet = Callsheet.new
        @departments = Department.where(production_id: current_user.default_working_production_id)
    end

    def edit
        @callsheet = Callsheet.find(params[:id])
    end

    def create
        @callsheet = Callsheet.new(callsheets_params)
        @Callsheet.production_id = current_user.default_working_production_id


        if @callsheets.save
            redirect_to callsheet_path
        else
            render 'new'
        end
    end

    def update
        @callsheet = Callsheet.find(params[:id])

        if @callsheet.update(callsheets_params)
            redirect_to callsheet_path, :notice => "callsheets successfully updated."
        else
            render 'edit', :notice => "callsheets not updated."
        end
    end

    def destroy
        @callsheet = Callsheet.find(params[:id])
        @callsheet.destroy

        redirect_to callsheets_path
    end

    private
        def callsheets_params
            params.require(:callsheet).permit(:crewmembers_params [:id, :firstname])

        end
end

新调用表的表单：

<%= form_for @callsheet do |f| %>
  <% if @callsheet.errors.any? %>
    <div id="error_explanation"  class="alert alert-danger">
      <strong>
      <%= pluralize(@callsheet.errors.count, "error") %> prohibited
      this call sheet from being saved:
      </strong>
      <ul>
        <% @callsheet.errors.full_messages.each do |msg| %>
          <li><%= msg %></li>
        <% end %>
      </ul>
    </div>
  <% end %>

  <%= f.fields_for :crewmember do |crewmember| %>
    <fieldset>
      <%= crewmember.label :firstname, "First Name" %><br />
      <%= crewmember.text_field :firstname %>
    </fieldset>
  <% end %>

<% end %>

Answer 1

您不需要attr_accessible（仅适用于 Rails 3）。

您还应该将所有模型重命名为snake_case，引用CamelCase：

#app/models/call_sheet.rb
class CallSheet < ActiveRecord::Base
   has_many :cast_members
   has_many :crew_members
   accepts_nested_attributes_for :crew_members
end

按照fields_for 的习惯，您还需要构建关联对象（如果您正在创建new 记录）（如果editing 则不需要这样做）：

#app/controllers/call_sheets_controller.rb
class CallSheetsController < ApplicationController
    before_action :set_departments

    def new
        @callsheet = Callsheet.new
        @callsheet.crew_members.build
    end

    def edit
        @callsheet = Callsheet.find params[:id]
    end

    def update
        @callsheet = Callsheet.find params[:id]
        @callsheet.update callsheet_params
    end

    private

    def set_departments
       @departments = Department.where(production_id: current_user.default_working_production_id)
    end

    def callsheet_params
       params.require(:callsheet).permit(crew_members_attributes: [:id, :firstname])
    end
end

这将允许您使用：

<%= form_for @callsheet do |f| %>
  <%= f.fields_for :crew_members do |crewmember| %>
      <%= crewmember.label :firstname, "First Name" %><br />
      <%= crewmember.text_field :firstname %>
  <% end %>
  <%= f.submit %>
<% end %>

--

通过fields_for传递嵌套属性时，需要几个组件：

• 父模型中的正确关联
• 关联模型的实例化版本 (@parent.build_child)
• 正确的fields_for 定义
• 通过控制器传递正确的parameters

我已经概述了如何实现上述目标，所有这些都是错误的。

---

您还可以在同一个调用中声明多个验证：

#app/models/crew_member.rb
class CrewMember < ActiveRecord::Base
   validates :firstname, :email, presence: true
end