| <xsl:choose> | |
| The <xsl:choose> element is XSLT's version of the switch or case statement found in many procedural programming languages. | |
| Category | |
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Instruction |
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| Required Attributes | |
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None. |
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| Optional Attributes | |
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None. |
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| Content | |
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Contains one or more <xsl:when> elements and might contain a single <xsl:otherwise> element. Any <xsl:otherwise> elements must be the last element inside <xsl:choose>. |
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| Appears in | |
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<xsl:choose> appears inside a template. |
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| Defined in | |
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XSLT section 9.2, Conditional Processing with xsl:choose. |
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| Example | |
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Here's an example that uses <xsl:choose> to select the background color for the rows of an HTML table. We cycle among four different values, using <xsl:choose> to determine the value of the bgcolor attribute in the generated HTML document. Here's the XML document we'll use: <?xml version="1.0"?> <list xml:lang="en"> <title>Albums I've bought recently:</title> <listitem>The Sacred Art of Dub</listitem> <listitem>Only the Poor Man Feel It</listitem> <listitem>Excitable Boy</listitem> <listitem xml:lang="sw">Aki Special</listitem> <listitem xml:lang="en-gb">Combat Rock</listitem> <listitem xml:lang="zu">Talking Timbuktu</listitem> <listitem xml:lang="jz">The Birth of the Cool</listitem> </list> And here's our stylesheet:
<?xml version="1.0"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="html"/>
<xsl:template match="/">
<html>
<head>
<title>
<xsl:value-of select="list/title"/>
</title>
</head>
<body>
<h1><xsl:value-of select="list/title"/></h1>
<table border="1">
<xsl:for-each select="list/listitem">
<tr>
<td>
<xsl:attribute name="bgcolor">
<xsl:choose>
<xsl:when test="position() mod 4 = 0">
<xsl:text>papayawhip</xsl:text>
</xsl:when>
<xsl:when test="position() mod 4 = 1">
<xsl:text>mintcream</xsl:text>
</xsl:when>
<xsl:when test="position() mod 4 = 2">
<xsl:text>lavender</xsl:text>
</xsl:when>
<xsl:otherwise>
<xsl:text>whitesmoke</xsl:text>
</xsl:otherwise>
</xsl:choose>
</xsl:attribute>
<xsl:value-of select="."/>
</td>
</tr>
</xsl:for-each>
</table>
</body>
</html>
</xsl:template>
</xsl:stylesheet>
We use <xsl:choose> to determine the background color of each generated <td> element. Here's the generated HTML document, which cycles through the various background colors: <html> <head> <META http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Albums I've bought recently:</title> </head> <body> <h1>Albums I've bought recently:</h1> <table border="1"> <tr> <td bgcolor="mintcream">The Sacred Art of Dub</td> </tr> <tr> <td bgcolor="lavender">Only the Poor Man Feel It</td> </tr> <tr> <td bgcolor="whitesmoke">Excitable Boy</td> </tr> <tr> <td bgcolor="papayawhip">Aki Special</td> </tr> <tr> <td bgcolor="mintcream">Combat Rock</td> </tr> <tr> <td bgcolor="lavender">Talking Timbuktu</td> </tr> <tr> <td bgcolor="whitesmoke">The Birth of the Cool</td> </tr> </table> </body> </html> When rendered, our HTML document looks like Figure A-5. Document cycling among different background colors |
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