Write C# in-built function in XSLT

First we have to add namespaces, then write the code.

XSLT File :  (datetime.xslt)

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:msxsl="urn:schemas-microsoft-com:xslt"  xmlns:myExtension="urn:myExtension"
                exclude-result-prefixes="msxsl myExtension">

  <xsl:output method="xml" indent="yes"/>

  <msxsl:script implements-prefix="myExtension" language="C#">
    <![CDATA[
     public string FormatDateTime(string xsdDateTime, string format)
      {
          DateTime date = DateTime.Parse(xsdDateTime);
          return date.ToString(format);
      }
     ]]>
  </msxsl:script>
  <xsl:template match="Date">
    <formattedDate>
      <xsl:value-of select="myExtension:FormatDateTime(self::node(), 'd')"/>
    </formattedDate>
  </xsl:template>
</xsl:stylesheet>


XML File:  (datetime.xml)

<?xml version="1.0" encoding="utf-8" ?>
<Date>2007-11-14T12:01:00</Date>


CALL on  program.aspx.cs page

 Xml1.DocumentSource = MapPath("datetime.xml");
 Xml1.TransformSource = MapPath("datetime.xslt");


OUTPUT:

11/14/2007