ruby-on-rails – Ruby on Rails – 更改事件的下拉框

这是一个使用 jquery-ujs(https://github.com/rails/jquery-ujs)的干净方法

在你看来：

<%= 
  SELEct_tag  
      :first_SELEct,# name of SELEctbox
      options_from_collection_for_SELEct(@myrecords,"id","name"),# your options for this SELEct box
      :'data-remote' => 'true',# important for UJS
      :'data-url' => url_for(:controller => 'MyController',:action => 'getdata'),# we get the data from here!
      :'data-type' => 'json' # tell jQuery to parse the response as JSON!
%>


<%= 
   SELEct_tag  
       :second_SELEct,# name of SELEctbox
       "<option>Please SELEct something from first SELEct!</option>"
%>

您的控制器：

class MyController < ApplicationController


  def getdata
    # this contains what has been SELEcted in the first SELEct box
    @data_from_SELEct1 = params[:first_SELEct]

    # we get the data for SELEctbox 2
    @data_for_SELEct2 = Mymodel.where(:some_id => @data_from_SELEct1).all

    # render an array in JSON containing arrays like:
    # [[:id1,:name1],[:id2,:name2]]
    render :json => @data_for_SELEct2.map{|c| [c.id,c.name]}
  end
end

在你的application.js中：

$(document).ready(function() {

  // #first_SELEct is the id of our first SELEct box,if the ajax request has been successful,// an ajax:success event is triggered.

  $('#first_SELEct').live('ajax:success',function(evt,data,status,xhr) {
    // get second SELEctbox by its id
    var SELEctbox2 = $('#second_SELEct');

    // empty it
    SELEctbox2.empty();

    // we got a JSON array in data,iterate through it

    $.each(data,function(index,value) {
      // append an option
      var opt = $('<option/>');

      // value is an array: [:id,:name]
      opt.attr('value',value[0]);
      // set text
      opt.text(value[1]);
      // append to SELEct
      opt.appendTo(SELEctbox2);
    });
  });

});