Question

我一直试图让一些动态选择功能正常工作，但尽管有许多不同的教程，我还没有让它工作。为了便于阅读，我将代码示例归结为基础知识。任何建议将不胜感激。

在故障页面上，我需要指定公司并联系故障，但我只希望能够看到与所选公司关联的联系人

Fault - belongs_to :company, :user, :contact
User - has_many :faults
Contacts - has_and_belongs_to_many :companies
Company - has_and_belongs_to_many :contacts, has_many :faults

/faults/_form.html.erb

<%= f.label :company, "Company:" %>

<%= collection_select(:fault,:company_id,@companies,:id,:full_name, :prompt => "Please select a company") %></br>

<%= f.label :contact, "Contact:" %>

<%= f.collection_select :contact_id, @contacts, :id, :name, :prompt => "Select a Contact" %>

<%= link_to "Add New Contact", {:controller => "companies", :action => "index"}, :confirm => "To add a contact for a company you need to do this from the companies page." %></br>

Answer 1

疑难杂症。使用UJS，您可以通过5个步骤动态填充您的选择。

在视图
添加JavaScript（或CoffeeScript）以观察select元素的更改
根据您的选择创建一个控制器方法来获取所需的信息
添加与新控制器方法匹配的路由
创建UJS视图以更新您的联系人选择

所以，

添加班级名称：

<%= f.label :company, "Company:" %>
<%= collection_select(:fault,:company_id,@companies,:id,:name, {:prompt => "Please select a company"}, {:class => "company_selection"}) %>
<%= f.label :contact, "Contact:" %>
<%= f.collection_select :contact_id, @contacts, :id, :name, {:prompt => "Select a Contact"}, {:class=>"contact_selection"} %>

投入一些CoffeeScript（app/assets/javascripts/faults.js.coffee）

$(document).ready ->
  $(".company_selection").on "change", ->
    $.ajax
      url: "/faults/get_contacts"
      type: "GET"
      dataType: "script"
      data:
        company_id: $('.company_selection option:selected').val()

更新您的故障控制器

def get_contacts
  @company = Company.find params[:company_id]
  @contacts = @company.contacts
end

为新方法添加路线

resources :faults do
  collection do
    get 'get_contacts', to: "faults#get_contacts"
  end 
end

添加UJS文件（app/views/faults/get_contacts.js.erb）

$('.contact_selection').empty();
$('.contact_selection').append( $('<option>Select the Contact</option>'));
<% @contacts.each do |contact| %>
  $('.contact_selection').append($('<option value="<%= contact.id %>"><%= contact.name %></option>'));
<% end %>

Answer 2

Vanilla JS Option

这只能通过香草javascript实现。确保companies/[id]/contacts.json处有一条路由返回正确的数据。

const select = document.querySelector('#company_id');
select.addEventListener('change',function(e) {
  axios.get(`/companies/${e.target.value}/contacts.json`)
    .then((res) => {
      let contactSelect = document.querySelector('#contact_id')
      contactSelect.innerHTML = ''
      res.data.map((model, i) => {
        contactSelect.options[i] = new Option(model.name, model.id);
      })
    })
});

Rails - 动态选择 - 集合选择

2 个答案:

Vanilla JS Option