现在我正在探索Magento管理部分的内部，我偶然发现了这个XML：
文件：app / design / adminhtml / default / default / layout / catalog.xml，第55行
50 <block type="core/template" template="catalog/wysiwyg/js.phtml"/> 51 </reference> 52 </adminhtml_catalog_product_new> 53 54 <adminhtml_catalog_product_edit> 55 <update handle="editor"/> 56 <reference name="content"> 57 <block type="adminhtml/catalog_product_edit" name="product_edit"></block> 58 </reference>
什么是< update />标签做？
< update>基本上拉另一个手柄。
假设你有这个：
<layout>
<foo>
<reference name="header">
<block type="cms/block" name="some_block" as="someBlock">
<action method="setBlockId"><block_id>some_block</block_id></action>
</block>
</reference>
<reference name="left">
<block type="cms/block" name="some_totally_different_block" as="someTotallyDifferentBlock">
<action method="setBlockId"><block_id>some_totally_different_block</block_id></action>
</block>
</reference>
</foo>
<bar>
<update handle="foo" />
<reference name="header">
<block type="cms/block" name="some_other_block" as="someOtherBlock">
<action method="setBlockId"><block_id>some_other_block</block_id></action>
</block>
</reference>
</bar>
</layout>
产生的条形码XML将是：
<layout>
<bar>
<reference name="header">
<!-- Start of part pulled in from foo -->
<block type="cms/block" name="some_block" as="someBlock">
<action method="setBlockId"><block_id>some_block</block_id></action>
</block>
<!-- End of part pulled in from foo -->
<block type="cms/block" name="some_other_block" as="someOtherBlock">
<action method="setBlockId"><block_id>some_other_block</block_id></action>
</block>
</reference>
<!-- Start of part pulled in from foo -->
<reference name="left">
<block type="cms/block" name="some_totally_different_block" as="someTotallyDifferentBlock">
<action method="setBlockId"><block_id>some_totally_different_block</block_id></action>
</block>
</reference>
<!-- End of part pulled in from foo -->
</bar>
</layout>
tl; dr：更新句柄基本上是“将此布局与我当前的布局合并”。
