使用XSLT修改XML文件中的属性

Question

I want to modify an XML file, I have some attributes in this XML file and I want to change this ie if the producer is VW, then Iwant to change the country to "Germany" hier is my XML:

<?xml version="1.0" encoding="utf-8"?>
<?xml-stylesheet type="text/xsl" href="example.xslt"?>
<Auto>
  <lkw producer="VW" country="USA">
    <name>Polo</name>
    <price>$5955.2</price>
    <color>red</color>
  </lkw>
  <lkw producer="Audi" country="germany">
    <name>A8</name>
    <price>$8955.2</price>
    <color>black</color>
  </lkw>
  <lkw producer="BMW" country="USA">
    <name>Polo</name>
    <price>$6955.2</price>
    <color>blue</color>
  </lkw>
 <lkw producer="VW" country="China">
    <name>Pasat</name>
    <price>$2955.2</price>
    <color>red</color>
  </lkw>
</Auto>

and this is my 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" exclude-result-prefixes="msxsl">
  <xsl:template match="@*|node()">
    <xsl:copy>
      <xsl:apply-templates select="@*|node()"/>
    </xsl:copy>
  </xsl:template>
  <xsl:template match="@producer[parent::VW]">
    <xsl:attribute name="country">
      <xsl:value-of select="'germany'"/>
    </xsl:attribute>
  </xsl:template>
</xsl:stylesheet>

but I see no change in my XML file, Could you please tell me, Where is my mistake in XSLT?

Answer 1

Looking at your current template...

<xsl:template match="@producer[parent::VW]">

This is actually equivalent to this...

<xsl:template match="VW/@producer">

So, it is looking for an element called VW , when you really want to be checking the value of the attribute.

What you are really trying to do, is match the @country attribute for elements which have an @producer attribute equal to VW

<xsl:template match="lkw[@producer='VW']/@country">
  <xsl:attribute name="country">
    <xsl:value-of select="'germany'"/>
  </xsl:attribute>
</xsl:template>