如何在嵌套表单中包含 id？

Question

我有一个嵌套表单，我想在商店模型中包含 city_id，这个 <%= s.hidden_​​field :city_id, @city.id %> 正确吗？如果是的话，我之后要在控制器中添加什么？如果这不是包含它的正确方法，有人可以告诉我正确的方法吗？非常感谢。

<%= form_for @deal ,:url=>{:action =>"create"} do |c|%>
  <%= c.text_field :item_name %>
  <%= c.text_field :price %>

  <%=c.fields_for :stores do |s| %>
    <%=s.text_field :store_name %>
    <%= s.hidden_field :city_id, @city.id %>
    <%=s.text_field :address %>
  <%end%>           

  <%= c.submit "post"%>     
<%end%>

控制器

def create
  @city = City.find(session[:city_id])
  @[email protected](params[:deal])

  if @deal.save
    redirect_to @deal
    flash[:notice]="successfully created"
  else
    render 'new' 
  end 
end

模型

class City < ActiveRecord::Base
    has_many :stores
    has_many :deals 
end

class Deal < ActiveRecord::Base
    belongs_to :city
    has_many :stores ,:through =>:store_deals
    has_many :store_deals
end

class StoreDeal < ActiveRecord::Base
    belongs_to :store
    belongs_to :deal
end

错误

NoMethodError in Deal#new

Showing /home/Deals/app/views/deal/new.html.erb where line #13 raised:

undefined method `merge' for 2:Fixnum
Extracted source (around line #13):

10: <tr><td><label>Price</label></td><td><%= c.text_field :price %></td></tr>
11: <%=c.fields_for :stores do |s| %>
12: <tr><td><label>Store</label></td><td><%=s.text_field :store_name %></td></tr>
13: <%= s.hidden_field :city_id, @city.id %>
14: <tr><td><label>Cross street</label></td><td><%=s.text_field :address %></td></tr>
15: <%end%>
16: <tr><td><%= c.submit "post"%></td></tr>

Answer 1

好的，现在我已经更仔细地查看了您的代码并看到了问题所在。 hidden_​​field 帮助器没有 value 作为其参数之一。使用：

<%= s.hidden_field :city_id, :value => @city.id %>

但是，由于迈克尔·杜兰特（Michael Durrant）指出的原因，最好在控制器中处理这个问题。