使用 before/after 放置块的 Magento XML 几乎不起作用

Magento XML using before/after to place blocks hardly ever works

提问by mike-source

I'm a front-end Magento dev, have built quite a few of my own themes and I want to understand Magento's XML block positioning better...

我是前端 Magento 开发人员，已经构建了很多我自己的主题，我想更好地了解 Magento 的 XML 块定位...

I normally use a local.xmlfile to manipulate everything, I can define a block as follows:

我通常使用一个local.xml文件来操作一切，我可以如下定义一个块：

<cms_index_index>
   <reference name="root">
      <block type="core/template" name="example_block" as="exampleBlock" template="page/html/example-block.phtml"/>
   </reference>
</cms_index_index>

This would create a block on the home page (cms_index_index) and since the block is created one level under root, I would normally call the block by adding:

这将在主页 ( cms_index_index)上创建一个块，并且由于该块是在 下一级创建的root，我通常会通过添加以下内容来调用该块：

<?php echo $this->getChildHtml('exampleBlock') ?>

...to 1column.phtml(or 2columns-left/right.phtml, 3columns.phtmletc). The block can be placed on any page by substituting cms_index_indexfor the appropriate page tag.

......到1column.phtml（或2columns-left/ right.phtml，3columns.phtml等等）。通过替换cms_index_index适当的页面标签，块可以放置在任何页面上。

I see stuff like the following throughout the core XML files, and in tutorials:

我在整个核心 XML 文件和教程中看到如下内容：

<reference name="root">
   <block type="core/template" name="example_block" before="content" template="page/html/example-block.phtml"/>
</reference>

contentis a block which is part of magento's general page structure and, from what I understand, before="content"should place it where you'd expect, without needing to use getChildHtml('exampleBlock'), so far so good... however, before/after hardly ever seems to work for me, and I frequently find myself resorting to the getChildHtml method as backup, which isn't always ideal, and means editing more .phtml files than necessary.

content是一个块，它是 magento 的一般页面结构的一部分，据我所知，before="content"应该把它放在你期望的地方，不需要使用getChildHtml('exampleBlock')，到目前为止这么好......但是，之前/之后似乎几乎没有工作我和我经常发现自己求助于 getChildHtml 方法作为备份，这并不总是理想的，并且意味着编辑比必要更多的 .phtml 文件。

I've tried:

我试过了：

<reference name="root">
   <block type="core/template" name="example_block" before="content" template="page/html/example-block.phtml"/>
</reference>

Nothing appears...

什么都没有出现...

<reference name="root">
   <block type="core/template" name="example_block" after="header" template="page/html/example-block.phtml"/>
</reference>

Still nothing.... I'm also aware of using before="-"or after="-"to place something before everything within it's parent block. I occasionally have some luck with that, but generally just get confused and frustrated.

仍然什么都没有......我也知道在它的父块中的所有东西之前使用before="-"或after="-"放置一些东西。我偶尔会有一些运气，但通常只是感到困惑和沮丧。

I've googled all over the place for 'magento xml before/after not working' and beginning to wonder if its just me this happens to... can anyone explain when I can and can't use before/after to position blocks? What's wrong with the above examples?

我在到处搜索“magento xml 之前/之后不工作”并开始怀疑它是否只是我这种情况发生......谁能解释我何时可以和不能使用之前/之后定位块？上面的例子有什么问题？

I'm in magento 1.7.0.2 (latest available at time of posting)

我在 magento 1.7.0.2（发布时最新可用）

The main motivation for this is to reduce the number of core .phtml files I need to edit just to add a getChildHtml(), so if there is another (XML) way to get around this I'd be interested to know...

这样做的主要动机是减少我需要编辑的核心 .phtml 文件的数量来添加一个getChildHtml()，所以如果有另一种（XML）方法来解决这个问题，我很想知道......

回答by Alan Storm

The beforeand afterattributes only work in one of two cases:

在before和after属性只有在两种情况之一的工作：

1. When you insert into a core/text_listblock
2. When your template block calls getChildHtmlwithout any parameters

1. 插入core/text_list块时
2. 当您的模板块在getChildHtml没有任何参数的情况下调用时

When you say

当你说

<reference name="root">
   <block type="core/template" name="example_block" before="content" template="page/html/example-block.phtml"/>
</reference>

you're telling Magento

你在告诉 Magento

Hey Magento, put the example_blockinside the rootblock.

嘿 Magento，把example_block里面的root块。

When you put a number of different blocks inside a parent, those blocks have an implicit order. For template blocks, this order doesn't matter, since those blocks are being explicitly rendered.

当您将多个不同的块放入父级时，这些块具有隐式顺序。对于模板块，此顺序无关紧要，因为这些块是显式呈现的。

<?php echo $this->getChildHtml('example_block') ?>

However, there's two cases where order matters. First, if you call

但是，有两种情况下顺序很重要。首先，如果你打电话

<?php echo $this->getChildHtml() ?>

from a template, then Magento will render allthe child blocks, in order.

从模板中，然后 Magento 将按顺序渲染所有子块。

Secondly, there's a special type of block called a "text list" (core/text_list/Mage_Core_Block_Text_List). These blocks render all their children automatically, again in order. The contentblock is an example of this

其次，有一种特殊类型的块，称为“文本列表”（core/text_list/ Mage_Core_Block_Text_List）。这些块再次按顺序自动渲染所有子项。该content块是一个例子

<block type="core/text_list" name="content"/>

That's why you can insert blocks into contentand they render automatically.

这就是为什么您可以将块插入其中content并自动渲染。

So, in your example above, you're inserting blocks into the rootblock. The rootblock is a template block whose phtml template uses getChildHtmlcalls with explicit parameters. Therefore the beforeand afterattributes don't do what you (and many others, including me) wish they did.

因此，在上面的示例中，您将块插入到root块中。该root块是一个模板块，其 phtml 模板使用getChildHtml带有显式参数的调用。因此before和after属性不会做你（和许多其他人，包括我）希望他们做的事情。