遍历使用xalan：nodeset获得的节点集时，xsl：key不起作用

Question

我发现xsl：key似乎无法正常工作的情况。
我正在将XSLT 1与Xalan（已编译）一起使用，这就是发生的情况：

1.-这有效：名为test1的键可以正常工作：

<xsl:variable name="promosRTF">
  <xsl:copy-of select="promo[@valid='true']"/>
</xsl:variable>
<xsl:variable name="promos" select="xalan:nodeset($promosRTF)" />

<!-- now the key: when defined and used here it works fine: -->
<xsl:key name="test1" match="//promo" use="'anytext'" />
<xsl:for-each select="key('test1','anytext')/*">
  loop through elements in key... ok, works fine
</xsl:for-each>

<xsl:for-each select="$promos/*">
  ..loop through elements in variable $promos ...it is not empty so the loop iterates several times
</xsl:for-each>

2.-这不起作用：现在在循环遍历xalan：nodeset获得的元素的循环内定义并使用了密钥test1（我想这是重点）。

<xsl:variable name="promosRTF">
  <xsl:copy-of select="promo[@valid='true']"/>
</xsl:variable>
<xsl:variable name="promos" select="xalan:nodeset($promosRTF)" />

<xsl:for-each select="$promos/*">
  <!-- now the key: when defined and used (or just used) inside this for-each loop it does nothing: -->
  <xsl:key name="test1" match="//promo" use="'anytext'" />
  <xsl:for-each select="key('test1','anytext')/*">
    loop through elements in key... NOTHING HERE, it does not work :(
  </xsl:for-each>

  ..loop through elements in variable $promos ...it is not empty so iterates several times
</xsl:for-each>

有人知道发生了什么吗？请注意，变量$ promos不是空的，因此循环实际上是迭代的，它是内部使用的键，什么也不做。

提前非常感谢您。

PS：在Martin回答之后，我发布了此备用代码，该代码也不起作用：

<xsl:variable name="promosRTF">
  <xsl:copy-of select="promo[@valid='true']"/>
</xsl:variable>
<xsl:variable name="promos" select="xalan:nodeset($promosRTF)" />

<!-- now the key: defined as a first level element: -->
<xsl:key name="test1" match="//promo" use="'anytext'" />
<xsl:for-each select="$promos/*">
  <!-- but used inside this for-each loop it does nothing: -->
  <xsl:for-each select="key('test1','anytext')/*">
    loop through elements in key... NOTHING HERE, it does not work :(
  </xsl:for-each>

  ..loop through elements in variable $promos ...it is not empty so iterates several times
</xsl:for-each>

解决方案：在Martin的评论中，问题的关键在于：结果树片段中的节点被视为另一个文档中的节点。
Martin也指出了解决方法：在XSLT 1.0中，您需要使用for-each更改上下文节点，然后在for-each中调用key。此代码将起作用：

<xsl:variable name="promosRTF">
  <xsl:copy-of select="promo[@valid='true']"/>
</xsl:variable>
<xsl:variable name="promos" select="xalan:nodeset($promosRTF)" />

<!-- now the key -->
<xsl:key name="test1" match="//promo" use="'anytext'" />
<xsl:for-each select="$promos/*">
  <!-- inside this for-each we are in a different *document*, so we must go back: -->
  <xsl:for-each select="/">
    <xsl:for-each select="key('test1','anytext')/*">
      loop through elements in key... and now IT WORKS, thanks Martin :)
    </xsl:for-each>
  </xsl:for-each>

  ..loop through elements in variable $promos ...it is not empty so iterates several times
</xsl:for-each>

Answer 1

xsl:key我很惊讶你将放入 中没有得到错误for-each。在http://www.w3.org/TR/xslt#key中，您可以看到 被xsl:key定义为<!-- Category: top-level-element -->顶级元素，因此您需要将其作为xsl:stylesheetor的子元素xsl:transform。