form_for 非 AR 模型 - fields_for Array 属性不迭代 [英] form_for non-AR model - fields_for Array attribute doesn't iterate

问题描述

我无法让 fields_for 处理非 ActiveRecord 模型的 Array 属性.

I'm having trouble getting fields_for to work on an Array attribute of a non-ActiveRecord model.

精炼下来，我必须遵循:

Distilled down, I have to following:

模型/parent.rb

models/parent.rb

class Parent
  extend ActiveModel::Naming
  include ActiveModel::Conversion
  include ActiveModel::Validations
  extend ActiveModel::Translation

  attr_accessor :bars
end

控制器/parent_controller.rb

controllers/parent_controller.rb

def new_parent
  @parent = Parent.new

  @parent.bars = ["hello", "world"]
  render 'new_parent'
end

views/new_parent.html.haml

views/new_parent.html.haml

= form_for @parent, :url => new_parent_path do |f|
  = f.fields_for :bars, @parent.bars do |r|
    = r.object.inspect

使用上面的代码，我的页面包含["hello", "world"]——也就是在分配给<的Array上调用inspect的结果代码>条形.(在 fields_for 行中省略了 @parent.bars，我只显示 nil).

With the code as above, my page contains ["hello", "world"] - that is, the result of inspect called on the Array assigned to bars. (With @parent.bars omitted from the fields_for line, I just get nil displayed).

如何使 fields_for 表现得像 AR 关联 - 也就是说，为我的 bars 数组的每个成员执行一次块中的代码?

How can I make fields_for behave as for an AR association - that is, perform the code in the block once for each member of my bars array?

推荐答案

我认为正确的技巧是:

= form_for @parent, :url => new_parent_path do |f|
  - @parent.bars.each do |bar|
    = f.fields_for "bars[]", bar do |r|
      = r.object.inspect

为什么不能将其制作为 Just Work 我不确定，但这似乎可以解决问题.

Quite why it can't be made to Just Work I'm not sure, but this seems to do the trick.

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