Ruby on rails RubyonRails-在habtm关系中创建子表

我有一个可以很好地创建的表列表。然后，我希望能够通过单击父表上的Edit（转到Edit.html.erb），然后单击New child来创建子表。父表和子表之间的关系是has_，并且_属于_many

<%= button_to 'New Child', new_parent_child_path([@parent, @parent.children.build]), :method => :get %>

服务器日志提供了以下信息：

Started GET "/parents/1//children/new" for blah at blah
Processing by ChildrenController#new as HTML
  Parameters: {"parent_id"=>"1"}
  Rendered children/_form.html.erb (1.3ms)
  Rendered children/new.html.erb within layouts/application (1.9ms)
Completed 500 Internal Server Error in 4ms

ActionView::Template::Error (undefined method `children' for nil:NilClass):
    1: <%= form_for ([@parent, @parent.children.build]) do |f| %>
    2: 
    3: <div class = "field">
    4:   <%= f.label :Child_name %><br/>
  app/views/children      /_form.html.erb:1:in`_app_views_children__form_html_erb__2140243687_70034946643120'
  app/views/children/new.html.erb:3:in `_app_views_children_new_html_erb__655166082_70034947829100'

---

您需要在新操作中包括

@parent=parent.find（params[：parent_id]）

，因为您正在new.html.erb模板中使用它。否则它将为零，

@parent.children.build

将不起作用。

您可以发布您的

新操作中的代码吗？已经添加了您请求的代码。您是一个绝对的明星，非常感谢！这件事我已经坚持了好几天了。我是个新手；我该如何说这是固定的，并为您提供站点使用的任何等效的rep/karma？欢迎！我将我的评论改为回答（见下文）。您可以单击复选标记以接受。有关更多信息，请参阅此链接：
Started GET "/parents/1//children/new" for blah at blah
Processing by ChildrenController#new as HTML
  Parameters: {"parent_id"=>"1"}
  Rendered children/_form.html.erb (1.3ms)
  Rendered children/new.html.erb within layouts/application (1.9ms)
Completed 500 Internal Server Error in 4ms

ActionView::Template::Error (undefined method `children' for nil:NilClass):
    1: <%= form_for ([@parent, @parent.children.build]) do |f| %>
    2: 
    3: <div class = "field">
    4:   <%= f.label :Child_name %><br/>
  app/views/children      /_form.html.erb:1:in`_app_views_children__form_html_erb__2140243687_70034946643120'
  app/views/children/new.html.erb:3:in `_app_views_children_new_html_erb__655166082_70034947829100'

<%= form_for ([@parent, @parent.children.build]) do |f| %>

<div class = "field">
  <%= f.label :Child_name %><br/>
  <%= f.text_field :ChildName %>
</div>

<div class = "field">
  <%= f.label :Child_email_address %><br/>
  <%= f.text_field :ChildEmail %>
</div>

<div class = "actions">
  <%= f.submit %>
</div>
<% end %>

  def new
    @child = Child.new
  end

  def create
    @parent = Parent.find(params [:parent_id])
    @scout = @parent.children.build(params[:child])
    redirect_to parent_path(@parent)
  end