Question

我是Ruby和Rails的新手，我很难获得选择下拉菜单，先显示当前年份，然后按降序返回30年。我使用form_for生成表单/字段。

我可以通过以下方式按升序运行：

<%= builder.label :modelyear, "Model Year" %>        
<%= builder.select :modelyear, (Time.zone.now.year - 30)..(Time.zone.now.year + 0) %>

这些不起作用：

<%= builder.label :modelyear, "Model Year" %>        
<%= builder.select :modelyear, (Time.zone.now.year)..(Time.zone.now.year - 30) %>

<%= builder.label :modelyear, "Model Year" %>        
<%= builder.select :modelyear, (Time.zone.now.year + 0)..(Time.zone.now.year - 30) %>

编辑：根据要求填写完整代码（原始尝试选择器）

<%= form_for(@user) do |f| %>
        <%= render 'shared/error_messages' %>

    <%= f.label :first_name %>
    <%= f.text_field :first_name %>
    <br /><br />

    <%= f.label :last_name %>
    <%= f.text_field :last_name %>
    <br /><br />

    <%= f.label :email %>
    <%= f.text_field :email %>
    <br /><br />

    <%= f.label :address1 %>
    <%= f.text_field :address1 %>
    <br /><br />

    <%= f.label :address2 %>
    <%= f.text_field :address2 %>
    <br /><br />

    <%= f.label :city %>
    <%= f.text_field :city %>
    <br /><br />

    <%= f.label :state %>
    <%= f.text_field :state %>
    <br /><br />

    <%= f.label :zipcode %>
    <%= f.text_field :zipcode %>
    <br /><br />

    <%= f.label :country %>
    <%= f.text_field :country %>
    <br /><br />

    <!-- Fields For Product -->
    <%= f.fields_for :products do |builder| %>
    <div>
             <%= builder.label :serial, "Serial Number" %>        
             <%= builder.text_field :serial %>
             <br /><br />


             <%= builder.label :modelyear, "Model Year" %>        
             <%= builder.select :modelyear, (Time.zone.now.year - 30)..(Time.zone.now.year + 0) %>
             <br /><br />

 </div>
<% end %>

<%= f.submit "Register Your Product", class: "button" %>

user.rb

    class User < ActiveRecord::Base
has_many :products, dependent: :destroy
accepts_nested_attributes_for :products, :allow_destroy => true
before_save { email.downcase! }
validates :first_name, presence: true
validates :last_name, presence: true
validates :email, presence: true
validates :address1, presence: true
validates :address2, length: { maximum: 30 }
validates :city, presence: true
validates :state, length: { maximum: 20 }
validates :zipcode, length: { maximum: 20 }
validates :country, presence: true
    end

product.rb

    class Product < ActiveRecord::Base
belongs_to :user
validates :serial, presence: true
validates :modelyear,     length: { maximum: 4 }
    end

Answer 1

试试这个：

<%= builder.select :modelyear, Time.zone.now.year.downto(Time.zone.now.year - 30)
.to_a, class:'form-control' %>

Answer 2

这应该有效

<%= builder.select :modelyear, ((Time.zone.now.year - 30)..(Time.zone.now.year + 0)).to_a.reverse %>

此处我将Range对象转换为Array，select也接受{{1}}作为参数。因此，您可以使用方便的数组reverse方法。

如何使form_for选择帮助显示日期按降序排列？

2 个答案: