Monday, 30 December 2013

Looping in XSLT: Recursive Template Calls

To loop in XSLT you need to call a template recursively.

In past I have done this using two approaches:

Option-1: While Loop
Logic is similar to a while loop. So the counter is decremented till it is greater than 0.
 
 
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
  <xsl:output indent="no" />
  <xsl:template match="/">
    <LoopInput>
      <xsl:call-template name="CreateLoop">
        <xsl:with-param name="count" select="${numLoop}" />
      </xsl:call-template>
    </LoopInput>
  </xsl:template>
  <xsl:template name="CreateLoop">
    <xsl:param name="count" />
    <xsl:if test="$count &gt; 0">
      <xsl:call-template name="CreateLoop">
        <xsl:with-param name="count" select="$count - 1" />
      </xsl:call-template>
      <Line>
        <xsl:text disable-output-escaping="no">Line Data: </xsl:text>
        <xsl:value-of select="$count" disable-output-escaping="no" />
      </Line>
    </xsl:if>
  </xsl:template>
</xsl:stylesheet>


Option-2: For Loop
Here counter is incremented from a initial count till it reaches the desired loop count.

 
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
  <xsl:output indent="no" />
  <xsl:template match="/">
    <LoopInput>
      <xsl:call-template name="CreateLoop">
        <xsl:with-param name="MaxLoop" select="${numLoop}" />
        <xsl:with-param name="iLoop" select="1" />
      </xsl:call-template>
    </LoopInput>
  </xsl:template>
  <xsl:template name="CreateLoop">
    <xsl:param name="MaxLoop" />
    <xsl:param name="iLoop" />
    <Line>
      <xsl:text disable-output-escaping="no">Line Data: </xsl:text>
      <xsl:value-of select="$iLoop" disable-output-escaping="no" />
    </Line>
    <xsl:if test="$iLoop &lt; $MaxLoop">
      <xsl:call-template name="CreateLoop">
        <xsl:with-param name="MaxLoop" select="$MaxLoop" />
        <xsl:with-param name="iLoop" select="$iLoop + 1" />
      </xsl:call-template>
    </xsl:if>
  </xsl:template>
</xsl:stylesheet>

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