How can I select the first element using XSLT?

问题:

I have a list of news items, sorted by dateCreated. I have a preview box control where I only want to show the first item. How can I do that using XSLT?

<xml>
    <news>
        <newsitem>
            <dateCreated>2009-09-09</dateCreated>
            <summary>Something great happened</sumamry>
        </newsitem>
        <newsitem>
            <dateCreated>2009-09-08</dateCreated>
            <summary>Something bad happened</sumamry>
        </newsitem>
        <newsitem>
            <dateCreated>2009-09-07</dateCreated>
            <summary>Something really bad happened</sumamry>
        </newsitem>
    </news>
</xml>

回答1:

If you wish to output XHTML 1.1, here's one way:

<?xml version="1.0"?>
<xsl:transform version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:xs="http://www.w3.org/2001/XMLSchema" exclude-result-prefixes="xsl xs">
<xsl:output mode="xhtml" version="1.1" omit-xml-declaration="yes" 
    encoding="utf-8" media-type="application/xhtml+xml" indent="no" 
    doctype-public="-//W3C//DTD XHTML 1.1//EN" 
    doctype-system="http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd" />

<xsl:template match="//newsItem[1]">
    <div><xsl:value-of select="dateCreated"/></div>
    <div><xsl:value-of select="summary"/></div>
</xsl:template>

</xsl:transform>

回答2:

//newsItem[1]

should do

回答3:

I had the same question and I think I found a better answer:

<xsl:for-each select="newsItem[1]">
  <div><xsl:value-of select="dateCreated"/></div>
  <div><xsl:value-of select="summary"/></div>
</xsl:for-each>

回答4:

//newsItem[1]

Selects the first book newsItem element, but note that IE5 and later has implemented that [0] should be the first node, but according to the W3C standard it should be [1]!