How do I pass a variable to XSLT XPath expression?

问题

How can I pass a variable to XSLT XPath. For example

  <ns0:UnitCode>
    <xsl:value-of select="//ns1:Root/InputMessagePart_1/
                          ns2:ServiceMasterDetailsResponse/
                          ns2:ServiceMasterDetailResponse[$Counter]/
                          ns2:BASE_UOM/text()"/>
  </ns0:UnitCode>

where Counter is my XSLT variable.

I want to pass the numeric value of the variable counter to the above XSLT XPath expression.

回答1:

How to Use Variable References in XSLT

XPath

Within a select attribute, use $var (as you've done):

 <xsl:value-of select="/path/to/element[@id=$var]"/>

Here are some other ways variable references can be used in XSLT...

Match patterns

XSLT 1.0: Variables are not allowed in match:

It is an error for the value of the match attribute to contain a VariableReference.

XSLT 2.0: Variables are allowed in match predicates or

Patterns may start with an id ^FO or key function call, provided that the value to be matched is supplied as either a literal or a reference to a variable or parameter, and the key name (in the case of the key function) is supplied as a string literal. These patterns will never match a node in a tree whose root is not a document node.

XSLT 2.0 Match Predicate Variable Example:

<xsl:variable name="globalVar" select="'value'"/>
<xsl:template match="abc[. = $globalVar]">

Literal result element

Within literal result element, use an attribute value template:

 <img src="{$var}/image.jpg"/>

Element or attribute name

Within an element or attribute name, use xsl:element or xsl:attribute and an attribute value template:

 <xsl:element name="{$var}">content</xsl:element>

or

 <xsl:attribute name="{$var}">content</xsl:attribute>

来源：https://stackoverflow.com/questions/36622647/how-do-i-pass-a-variable-to-xslt-xpath-expression