The <xsl:choose> element provides a mechanism for either/or processing: <xsl:choose> contains a series of <xsl:when> elements that are tested in order from top to bottom until a match is found. An <xsl:otherwise> element can be used to insert a template if no match is found.
The following code can be added to the example in the previous topic to color-code the rows by price. Rows 0-25 are displayed in green, rows 25-50 are displayed in blue, and rows 50 and higher are displayed in red. The color is changed by conditionally generating a portion of the value of the STYLE attribute on the table row.
<TR>
<xsl:attribute name="STYLE">color:
<xsl:choose>
<xsl:when test="price[. < 25]">green</xsl:when>
<xsl:when test="price[. < 50]">blue</xsl:when>
<xsl:otherwise>red</xsl:otherwise>
</xsl:choose>
</xsl:attribute>
<TD>
This example uses an XML source file and an XSLT style sheet.
XML File (portfolio-choose.xml)
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="portfolio-choose.xsl"?>
<portfolio xmlns:dt="urn:schemas-microsoft-com:datatypes" xml:space="preserve">
<stock exchange="nyse">
<name>zacx corp</name>
<symbol>ZCXM</symbol>
<price dt:dt="number">28.875</price>
</stock>
<stock exchange="nasdaq">
<name>zaffymat inc</name>
<symbol>ZFFX</symbol>
<price dt:dt="number">92.250</price>
</stock>
<stock exchange="nasdaq">
<name>zysmergy inc</name>
<symbol>ZYSZ</symbol>
<price dt:dt="number">20.313</price>
</stock>
</portfolio>
XSLT File (portfolio-choose.xsl)
<?xml version='1.0'?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
<xsl:template match="/">
<HTML>
<BODY>
<TABLE BORDER="2">
<TR>
<TD>Symbol</TD>
<TD>Name</TD>
<TD>Price</TD>
</TR>
<xsl:for-each select="portfolio/stock">
<TR>
<xsl:attribute name="STYLE">color:
<xsl:choose>
<xsl:when test="price[. < 25]">green</xsl:when>
<xsl:when test="price[. < 50]">blue</xsl:when>
<xsl:otherwise>red</xsl:otherwise>
</xsl:choose>
</xsl:attribute>
<TD>
<xsl:value-of select="symbol"/>
<xsl:if test="@exchange[.='nasdaq']">*</xsl:if>
</TD>
<TD><xsl:value-of select="name"/></TD>
<TD><xsl:value-of select="price"/></TD>
</TR>
</xsl:for-each>
</TABLE>
<P>* Listed on Nasdaq stock exchange</P>
<P>Price key: <SPAN STYLE="color:green">less than 25</SPAN>,
<SPAN STYLE="color:blue">25-50</SPAN>,
<SPAN STYLE="color:red">50+</SPAN>.</P>
</BODY>
</HTML>
</xsl:template>
</xsl:stylesheet>
Formatted Output
