Rails 4集合局部渲染

Question

我显然在做错了什么，但我不明白它。

我有一个部分调用，如下所示：

= render 'shared/purchase', collection: @purchases

@purchases在控制器中被定义如下：

@purchases = current_user.purchases

但是我遇到了这个错误：

app/views/shared/_purchase.html.slim where line #3 raised:

undefined local variable or method `purchase' for #<<Class:0x007fd8ca54f970>:0x007fd8ca54eb60>

然而，当我将局部更改为仅呈现local_assigns时，我看到了这个：

[:collection, #<ActiveRecord::Associations::CollectionProxy [#<Purchase id: 40, user_id: 20, purchaseable_id: 6, purchaseable_type: "PurchaseType", frequency: "Weekly", day: "Su", notes: "leave at gate", allergies: "peanuts", created_at: "2013-07-24 16:58:08", updated_at: "2013-07-24 16:58:08", size: "Normal", quantity: 2>, #<Purchase id: 41, user_id: 20, purchaseable_id: 5, purchaseable_type: "PurchaseType", frequency: "Weekly", day: "Su", notes: "leave at gate", allergies: "peanuts", created_at: "2013-07-24 16:58:08", updated_at: "2013-07-24 16:58:08", size: "Jumbo", quantity: 3>, #<Purchase id: 42, user_id: 20, purchaseable_id: 7, purchaseable_type: "PurchaseType", frequency: "Weekly", day: "Su", notes: "leave at gate", allergies: "peanuts", created_at: "2013-07-24 16:58:08", updated_at: "2013-07-24 16:58:08", size: nil, quantity: 1>, #<Purchase id: 43, user_id: 20, purchaseable_id: 8, purchaseable_type: "PurchaseType", frequency: "Weekly", day: "Su", notes: "leave at gate", allergies: "peanuts", created_at: "2013-07-24 16:58:08", updated_at: "2013-07-24 16:58:08", size: nil, quantity: 1>]>]
[:purchase, nil]

为什么每个集合项没有被作为本地变量purchase捕获？

我很困惑，我确信这是一个愚蠢的问题。我之前多次做过类似的事情，甚至将旧的工作代码与这个进行比较，但我无法弄清楚问题出在哪里。要么这是一个新的Rails 4功能，在文档中我没有看到，要么我就是个笨蛋。

谢谢！

- goddamnyouryan

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Rails文档提供了一个使用render的partial参数的示例(<%= render partial: "product", collection: @products %>)。我不确定这是否会有所不同，但值得一试。 - Kyle Decot

@KyleDecot 是的，完全正确。多么愚蠢的错误啊。如果你回答了，我会给你功劳。 - goddamnyouryan

一点也不傻。我也会期望它能够正常工作。 - Kyle Decot

刚刚花了太多时间与这个问题纠结！谢谢Kyle Decot！ - danielricecodes

哈哈，一样的问题 - 这让我感到很烦恼，因为我认为我已经完全按照文档操作了。 - DavidM

Answer 1

Rails文档中关于Rails中的布局和渲染的内容，使用了render函数的partial参数举例说明：Layouts and Rendering in Rails。

<h1>Products</h1>
<%= render partial: "product", collection: @products %>

- Kyle Decot