collection_select 内容未显示

Question

我目前正在尝试通过 collection_select 表单显示内容所标识的组织。

问题是在创建新联系人并选择组织后。组织不显示。

到目前为止，我已尝试在网上搜索答案，但没有任何帮助。我也尝试了所有我能想到的代码问题。

这是我的模型：

class Contact < ApplicationRecord
has_many :contact_orgs
has_many :organizations, through: :contact_orgs
accepts_nested_attributes_for :organizations
end

class Organization < ApplicationRecord
has_many :contact_orgs
has_many :contacts, through: :contact_orgs
end

class ContactOrg < ApplicationRecord
belongs_to :contact
belongs_to :organization
accepts_nested_attributes_for :organization
end

这是我的 schema.rb：

create_table "contact_orgs", force: :cascade do |t|
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.integer "contact_id"
t.integer "organization_id"
t.index ["contact_id"], name: "index_contact_orgs_on_contact_id"
t.index ["organization_id"], name: "index_contact_orgs_on_organization_id"
end

create_table "contacts", force: :cascade do |t|
t.string "first_name"
t.string "last_name"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end

create_table "organizations", force: :cascade do |t|
t.string "name"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.string "industry"
end

这是我的 contact_controller.rb：

private
def contact_params
params.require(:contact).permit(:first_name, :last_name, 
organizations_attributes: [:name, :industry])
end

def new
@contact = Contact.new
end

def show
@contact = Contact.find(params[:id])
end

def create
@contact = Contact.new(contact_params)
if @contact.save
redirect_to @contact
else
render 'new'
end
end

这是我的contact/new.html.erb：

<%= form_with scope: :contact, url: contact_path, local: true do |form| %>

<p>
<%= form.label :first_name %><br>
<%= form.text_field :first_name %>
</p>

<p>
<%= form.label :last_name %><br>
<%= form.text_field :last_name %>
</p>

<p>
<%= form.label :organization_id, "Organization:" %><br>
<%= form.collection_select :organization_id, Organization.order(:name), :id, :name, {}, {multiple: true} %>
</p>

<p>
<%= form.submit %>
</p>
<% end %>

这是我的contact/show.html.erb：

<p>
<strong>First name:</strong>
<%= @contact.first_name %>
</p>

<p>
<strong>Last Name:</strong>
<%= @contact.last_name %>
</p>
<hr>

<p>
<strong>Organizations:</strong>
<ul>
<% @contact.organizations.each do |organization| %>
<li><%= organization.name %></li>
<% end %>

</ul>
</p>

当我刷新我的 localhost:3000/contact/2 页面时，我的 Rails Server 显示的内容如下。

这是我的 Rails 控制台中的内容：

2.4.1 :001 > Contact.find(2).organizations
Contact Load (0.2ms)  SELECT  "contacts".* FROM "contacts" WHERE "contacts"."id" = ? LIMIT ?  [["id", 2], ["LIMIT", 1]]
Organization Load (0.2ms)  SELECT  "organizations".* FROM "organizations" INNER JOIN "contact_orgs" ON "organizations"."id" = "contact_orgs"."organization_id" WHERE "contact_orgs"."contact_id" = ? LIMIT ?  [["contact_id", 2], ["LIMIT", 11]]=> #<ActiveRecord::Associations::CollectionProxy []> 

这是我的 routes.rb 文件：

Rails.application.routes.draw do
get 'welcome/index'

resources :contacts, :organizations

root 'welcome#index'
end

提前谢谢你:)

编辑： 通过 Rails c 命令添加了 Contacts#Show 方法和 Contact.find(2).organization。

添加了 routes.rb

Answer 1

由于您使用的是连接表 (ContactOrg)，因此您在创建 Contact 时确实是在尝试创建新的 ContactOrg 记录，而不是将其分配给 Organization，这就是您的代码读取方式.

编辑

虽然我上面的第一个陈述仍然有一点（一点）优点（您实际上是在创建一个连接记录），但您绝对可以让 rails 帮助您，并且您的原始答案非常接近。这里的代码只在有更新的地方，我试图突出显示变化。

app/models/contact.rb

class Contact < ApplicationRecord
  has_many :contact_orgs
  has_many :organizations, through: :contact_orgs

  accepts_nested_attributes_for :organizations # you were correct here
end

app/views/contact/new.html.erb

<%= form_with model: :contact, local: true do |form| %>
  # use :model here so you can ultimately use this form for both new and edit.
  # The model method will infer the correct path

  ... contact fields here as you have them ...

  <p>
    <%= form.collection_select :organization_ids, Organization.order(:name), :id, :name, {}, {multiple: true} %>
    # the attribute for organization_id should be plural because you're accepting multiple
  <p>

  <p>
    <%= form.submit %>
  </p>
<% end %>

app/controllers/contacts_controller.rb

class ContactsController < ApplicationController


  ... new, show, and create as you have them ...

   private # private methods should go after all public methods 

   def contact_params
     params.require(:contact).permit(:first_name, :last_name, organization_ids: [])
     # again, the attribute you're passing in is called organization_ids, and you give it an empty array
   end
end

Answer 2

您的 contract_controller 没有初始化 show.html.erb 中使用的 @contact，因为没有任何 show 方法可以做到这一点。

尝试添加contact_controller

def show
  @contact = Contact.find(param[:id])
end

PS：当你调用 show 方法时，一定要传递给它一个contact.id

希望对你有所帮助。

Answer 3

有两个问题：

1. 您无法将组织保存到您的合同中。 您可以通过 Contact.find(2).organizations 查看您的 rails c。
2. 我们从不使用在私有方法中编写 new 和 create。

您的私有方法不应包含任何凝乳。

在您的 app/controllers/contacts_controller.rb

中

private

def contact_params
  params.require(:contact).permit(
    :first_name, 
    :last_name, 
    organizations_attributes: [
      :name, 
      :industry
    ]
 )
end

在您的app/views/contact/new.html.erb

中

<%= form_with scope: :contact, url: contact_index_path, local: true do |form| %>

  <p>
    <%= form.label :first_name %><br>
    <%= form.text_field :first_name %>
  </p>

  <p>
    <%= form.label :last_name %><br>
    <%= form.text_field :last_name %>
  </p>

  <p>
    <%= form.fields_for :organizations do |o| %>
      <%= o.label :organization %><br>
      <%= o.collection_select(:organization_id, Organization.all,
                          :id, :org_name,
                          {:prompt => 'Please select the organization'}) %>
  </p>

  <p>
    <%= form.submit %>
  </p>
<% end %>