Question

我想将Active Record结果打印到我的视图中...通常我会这样做：

<% if channelList.present? %>
<% channelList.each do |channel| %>
    <li>
      <div class="bp-movies-list-movie">
        <div class="bp-channel-list-image">
          <img src="<%= channel.channelimage %>"/>

但如果我这样做，我收到了这个错误：

undefined method `channelimage' for #<Channel::ActiveRecord_Relation:0x007f2189489bd8>

我的channelList对象如下所示：

[#<ActiveRecord::Relation [#<Channel id: 1, channelname: "Smart", created_at: "2016-04-24 13:47:11", updated_at: "2016-05-05 07:40:21", channeldescription: "Coole Smarts", channelprice: 1.0, currency: "€", free: false, locked: true, channelimage: "Screenshot_2016.04.09_16h24m03s_007_.png", knowledgeprovider_id: 1>, #<Channel id: 2, channelname: "Zimmer", created_at: "2016-05-04 21:20:59", updated_at: "2016-05-04 21:20:59", channeldescription: "asdad", channelprice: 1.0, currency: "€", free: false, locked: false, channelimage: "_SEE7468.jpg", knowledgeprovider_id: 1>]>, #<ActiveRecord::Relation [#<Channel id: 5, channelname: "Emies erster Channel", created_at: "2016-05-05 08:57:56", updated_at: "2016-05-05 08:57:56", channeldescription: "asdasd", channelprice: 1.0, currency: "€", free: false, locked: false, channelimage: "2015-12-26_12.20.07.jpg", knowledgeprovider_id: 3>]>]

我的问题在哪里？

更新

获取数据：

@channelList = Array.new

@knowledgeproviderList = @user.knowledgeprovider

@knowledgeproviderList.each do |kp|
  @c = Channel.where("knowledgeprovider_id = ?", kp.id)
  puts @c.inspect
  @channelList.push @c
end

Answer 1

这个循环的Instread，并执行多个sql查询，将结果添加到数组......

@channelList = Array.new

@knowledgeproviderList = @user.knowledgeprovider

@knowledgeproviderList.each do |kp|
  @c = Channel.where("knowledgeprovider_id = ?", kp.id)
  puts @c.inspect
  @channelList.push @c
end

映射ID并执行一个查询

@knowledgeproviderList = @user.knowledgeprovider
@channelList = Channel.where(knowledgeprovider_id: @knowledgeproviderList.map(&:id))

Answer 2

出于某种原因，channelList似乎是嵌套在数组中的ActiveRecord::Relation。

我愿意下注<% channelList.each do |channel| %>改为<% channelList.first.each do |channel| %>解决此特定错误。

如果您包含控制器代码，则可能会对此问题有所了解。

Answer 3

只需将您的控制器代码更改为如果每个knowledgeprovider_id有一个频道

@channelList = Array.new

@knowledgeproviderList = @user.knowledgeprovider

@knowledgeproviderList.each do |kp|
  @c = Channel.where("knowledgeprovider_id = ?", kp.id).first
  puts @c.inspect
  @channelList.push @c
end

如果可能有多个频道而不是更改视图代码，请执行以下操作：

<% if channelList.present? %>
<% channelList.each do |channels| %>
   <% channels.each do |channel| %>
    <li>
      <div class="bp-movies-list-movie">
        <div class="bp-channel-list-image">
          <img src="<%= channel.channelimage %>"/>

Rails Active Record迭代和打印结果返回异常错误

3 个答案: