如何使用枚举(rails 4.1)？

Question

我正在尝试在我的项目中使用枚举.但我不知道如何将它与simple_form输入集合一起使用.我的代码出错了.这是我在user.rb中的枚举定义:

    enum role: [ :guest, :super_admin, :advertiser, :publisher, :account_manager]

这是我的查看代码:

<%= simple_form_for(resource, as: resource_name, url: registration_path(resource_name)) do |f| %>
    <%= render 'devise/shared/error_messages', object: f.object %>
    <div class="form-inputs">
       <%= f.input :name, required: true, autofocus: true%>
       <%= f.input :email, required: true %>
      <%= f.input :password, required: true, placeholder: "min. 6 characters",
                  input_html: {"parsley-minlength" => 6, "error-container" =>"#errorBlock"} %>
      <%= f.input :password_confirmation, required: true,
                  input_html: {"parsley-equalto" => "#user_password"} %>
      **<%= f.input :role, collection: User.roles %>**

    </div>

Answer 1

当你做类似的事情时Resource.roles,会返回键和值的散列

{"guest"=>0, "super_admin"=>1, ...}

但是,如果您enum在表单中使用它,默认情况下它将显示一个整数字段.使用simple_form,您可以为其指定集合集,enum它将返回键的数组.

<%= f.input :role, collection: User.roles.keys %>

传入collection:选项后,它会自动将输入字段更改为选择.但是,您也可以手动指定as: :select或使用复选框.

请注意,User.roles.keys将返回

["guest", "super_admin", ... ]

这应该可以修复您收到的错误消息.之前,它显示枚举名称,选择设置枚举的整数值.为枚举属性设置值时,实际上是指定键名,而不是整数值.

这是来自文档http://edgeapi.rubyonrails.org/classes/ActiveRecord/Enum.html#method-i-inherited

class Conversation < ActiveRecord::Base
  enum status: [ :active, :archived ]
end

# conversation.update! status: 0
conversation.active!
conversation.active? # => true
conversation.status  # => "active"

# conversation.update! status: 1
conversation.archived!
conversation.archived? # => true
conversation.status    # => "archived"

# conversation.update! status: 1
conversation.status = "archived"

# conversation.update! status: nil
conversation.status = nil
conversation.status.nil? # => true
conversation.status      # => nil

注意他们设置状态值的位置conversation.status = "archived",他们设置枚举的键名而不是值1.希望这对您有所帮助.