XSLT - Lookup value from other part of xml inside foreach - xslt

Question

I have the following XML.
<?xml version="1.0" ?>
<Root xmlns="http://1.local/1.xsd">
<Definitions>
<FileTypes>
<FileType ID="1" Name="FileType1"/>
<FileType ID="2" Name="FileType2"/>
<!--... - lots of file types-->
<FileTypes>
</Definitions>
<Files>
<File Name="File1" FileTypeID="1" />
<File Name="File2" FileTypeID="1" />
<File Name="File3" FileTypeID="2" />
<!--... - lots of files-->
<Files>
</Root>
For each file, I need to get its Name attribute and for its FileTypeID lookup corresponding file type name
So example output would be:
File name: File1
File type: FileType1
File name: File2
File type: FileType1
File name: File3
File type: FileType2
This is XSLT I have so far but I'm not sure how to lookup name of file type.
<?xml version="1.0"?>
<xsl:stylesheet
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:l="http://1.local/1.xsd"
exclude-result-prefixes="l"
version="1.0">
<xsl:output method="text" omit-xml-declaration="yes" media-type="text/plain" />
<xsl:template match="/">
<xsl:apply-templates select="l:Root/l:Files" />
</xsl:template>
<xsl:template match="l:Root/l:Files">
Why
<xsl:for-each select="l:File">
File name: <xsl:value-of select="#Name">
File type:
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>

Answer 1

Use a xsl:key here to look up the FileTypes
<xsl:key name="FileTypes" match="l:FileType" use="#ID" />
Then, to get the relevant FileType name, you would do this
<xsl:value-of select="key('FileTypes', #FileTypeID)/#Name" />
Try this XSLT
<xsl:stylesheet
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:l="http://1.local/1.xsd"
exclude-result-prefixes="l"
version="1.0">
<xsl:output method="text" omit-xml-declaration="yes" media-type="text/plain" />
<xsl:key name="FileTypes" match="l:FileType" use="#ID" />
<xsl:template match="/">
<xsl:apply-templates select="l:Root/l:Files" />
</xsl:template>
<xsl:template match="l:Files">
<xsl:for-each select="l:File">
File name: <xsl:value-of select="#Name" />
File type: <xsl:value-of select="key('FileTypes', #FileTypeID)/#Name" />
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>
(Note your XML is not well-formed, as you do not have correct closing tags for FileTypes and Files.)

Answer 2

If you want to work with XSLT you need to start with understanding its expression language XPath to navigate XML trees, you can select //l:FileType[#ID = current()/#FileTypeID]/#Name. Or in XSLT, as Tim has already posted, you can use a key to efficiently implement the lookup.

Answer 3

You can try the following XSL.
<xsl:stylesheet
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:l="http://1.local/1.xsd"
exclude-result-prefixes="l"
version="1.0">
<xsl:output method="text" omit-xml-declaration="yes" media-type="text/plain" />
<xsl:template match="/">
<xsl:apply-templates select="l:Root/l:Files" />
</xsl:template>
<xsl:template match="l:Root/l:Files">
Why
<xsl:for-each select="l:File">
File name: <xsl:value-of select="#Name"/>
File type: <xsl:value-of select="//l:FileTypes/l:FileType[#ID=current()/#FileTypeID]/#Name"/>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>
Also, you need to make sure you put the correct namespace in your xsl transformation to actually match the values in you XML, and you were missing a few close tags in your XML.
For completeness I've included the fixed XML that I used for the solution
<Root xmlns="http://1.local/1.xsd">
<Definitions>
<FileTypes>
<FileType ID="1" Name="FileType1"/>
<FileType ID="2" Name="FileType2"/>
<!--... - lots of file types-->
</FileTypes>
</Definitions>
<Files>
<File Name="File1" FileTypeID="1" />
<File Name="File2" FileTypeID="1" />
<File Name="File3" FileTypeID="2" />
<!--... - lots of files-->
</Files>
</Root>