使用复选框过滤记录 [英] Using checkboxes to filter records

问题描述

我试图从零编程经验学习rails，并有一个应用程序，我试图做。在这里的人的帮助下，我有一个索引页的场地，可以通过下拉菜单通过它们属于哪个区域。我想能够有相同的影响，但使用复选框，还能够选择多个区域添加到过滤器。这是我到目前为止：

模型：

 地点& ActiveRecord :: Base 
 belongs_to：user 
 has_many：reviews 
 belongs_to：area 
 
 scope：north，where（：area_id =>2）
 scope：west，where（：area_id =>3）
 scope：south，where（：region_id =>4）
 end 
  

控制器：

  def index 
 if（params [：area]&&& Area.all.collect（&：name）.include？（params [：area] [：name]））
 @venues = Venue.send params [：area] [：name] .downcase）
 else 
 @venues = Venue.all 
 end 
 end 
  pre> 
 
 
 Venues index.html.erb：
 < div class =filter_options_container> 
 
< form class =filter_form，method =get> 
<％= select（area，name，Area.all.collect（&：name），{：prompt =>'All Areas'}）％>< br& 
< input type =submitvalue =Filter/> 
< / form> 
 
< br>< br> 
 
< form class =filter_form，method =get> 
<％Area.find（：all）.each do | a | ％> 
<％= check_box_tag（area，name）％> 
<％= a.name％> 
<％end％> 
< input type =submitvalue =Filter/> 
< / form> 
< / div> 
 
< div class =venue_partials_container> 
<％= render：partial => 'venue'，：collection => @venues％> 
< div class =clearall>< / div> 
<％= link_to'添加新场地'，new_venue_path，：class => add_new_venue_button％> 
< / div> 
 
 filter_options_container中的第一个表单（下拉列表）工作正常，但复选框返回无法将Symbol转换为Integer我失踪/做错了什么？
 
 
 
谢谢任何帮助。
解决方案
我不知道是什么导致你的错误，但我可以告诉你， check_box_tag 帮助器不工作你期望它的方式。从文档，它的定义如下：
  check_box_tag（name，value =1，checked = false，options = {}）
  / pre> 
 
 
因此，重复调用 check_box_tag（area，name） $ c>< input id =areaname =areatype =checkboxvalue =name/> 请注意，value属性（这是在提交表单时发送到您的服务器的值）始终为name - 而不是您想要的！
 
 
 
请尝试以下操作：
 <％Area.all.each do | a | ％> 
<％= check_box_tag（areas []，a.id）％> 
<％= h a.name％> 
<％end％> 
  
我更改的东西：
 
 
我使用 Area.all 而不是 Area.find（：all）  -  I但是DanneManne的回答声称它已经在Rails 3中过时了（我不知道 - 我仍然在2.3.8）。
 
 
我使用区域的ID而不是其在值字段中的名称;如果可以 -  ID是整数，并且比字符串比较快，并且在数据库中的id列上总是有一个索引用于超快速查找，那么通过ID查找事物总是好的。
 
 
最后，但最重要的是，在输入名称后面加入 [] 。这使得Rails收集使用这个名称提交的所有值到数组中，而不是只取最后一个。如下：
 
 
投掷网址... 
  / whatever？a = 3& a = 17& a = 12 
  
。 ..在一个Rails应用程序给你的params哈希... 
  {：a => 12} 
  
 ...但是网址... 
  / whatever？a [] = 3& a [] = 17& a [] = 12 
  
 ...给你想要的：
  {：a = >> [3，17，12]} 
  
如果你有一个数组的所有area_ids有兴趣的人，你可以得到所有在任何在这些区域的一个线索的场地（不是Rails好吗？）：
  filtered_venues = Venue.all（：conditions => {：area_id => params [：areas]}）
  
在调用finder之前，确保你有一个有效的区域ID数组 - 如果你不这样做，你的条件哈希将计算为{：area_id => nil} Rails会找到所有没有area_id的场所 - 可能没有，绝对不是你想要的。
 
 
 
希望这有助于！
 
I am trying to learn rails from zero programming experience and have an app im trying to make. With much help from people on here, I have an index page of venues which are filterable by which area they belong to via a dropdown menu. I would like to be able to have the same affect but using checkboxes and also being able to select multiple areas to add to the filter. This is what I have so far:

Model :
class Venue < ActiveRecord::Base
  belongs_to :user
  has_many :reviews
  belongs_to :area

  scope :north, where(:area_id => "2")
  scope :west, where(:area_id => "3")
  scope :south, where(:area_id => "4")
end
Controller:
def index
  if (params[:area] && Area.all.collect(&:name).include?(params[:area][:name]))
    @venues = Venue.send(params[:area][:name].downcase)
  else
    @venues = Venue.all
  end
end
Venues index.html.erb:
<div class="filter_options_container">

  <form class="filter_form", method="get">
    <%= select("area", "name", Area.all.collect(&:name), {:prompt => 'All Areas'}) %><br>
    <input type="submit" value="Filter" />
  </form>

  <br><br>

  <form class="filter_form", method="get">
    <% Area.find(:all).each do |a| %>
      <%= check_box_tag("area", "name") %>
      <%= a.name %>
    <% end %>
    <input type="submit" value="Filter" />
  </form>
</div>

<div class="venue_partials_container">
  <%= render :partial => 'venue', :collection => @venues %>
  <div class="clearall"></div>
  <%= link_to 'add a new venue', new_venue_path, :class => "add_new_venue_button" %>
</div>
The first form (the dropdowns) in the filter_options_container works fine but the checkboxes (the second form) is returning "can't convert Symbol into Integer" what am I missing/doing wrong?

Thankyou for any help.
解决方案
I don't know exactly what's causing your error, but I can tell you that the check_box_tag helper isn't working the way you expect it to.  From the documentation, it's defined like this:
check_box_tag(name, value = "1", checked = false, options = {})
So calling check_box_tag("area", "name") repeatedly will just give you <input id="area" name="area" type="checkbox" value="name" /> multiple times.  Note that the "value" attribute (which is the value that gets sent to your server when that form is submitted) is always "name" - not what you want!

Instead, try the following:
<% Area.all.each do |a| %>
    <%= check_box_tag("areas[]", a.id) %>
    <%=h a.name %>
<% end %>
The things I've changed:

I used Area.all instead of Area.find(:all) - I did it for cosmetic reasons, but DanneManne's answer claims it's obsolete in Rails 3 (I wouldn't know - I'm still on 2.3.8).
I used the area's ID instead of its name in the value field; it's always good to look things up by ID if you can - IDs are integers, and compare faster than strings, and there'll always be an index on the id column in your database for extra-fast lookups.
And last, but way most importantly I threw in [] after the  input name.  This lets Rails collect all the values submitted with this name into an array, rather than just taking the last one.  See below:
Throwing the URL...
/whatever?a=3&a=17&a=12
...at a Rails app gives you the params hash...
{:a => 12}
...but the URL...
/whatever?a[]=3&a[]=17&a[]=12
...gives you what you want:
{:a => [3, 17, 12]}
And if you have an array of all the area_ids you're interested in, you can get all the venues that are in any of those areas in a one-liner (isn't Rails great?):
filtered_venues = Venue.all(:conditions => {:area_id => params[:areas]})
Just make sure you have a valid array of area ids before calling that finder - if you don't, your conditions hash will evaluate to {:area_id => nil}, and Rails'll find you all the venues that don't have an area_id - probably none, and definitely not what you want.

Hope this helps!

                        
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