How to: Evaluate an XPath Expression

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You can evaluate XPath expressions with the QuickWatch dialog box. The XPath expression must be valid according to the W3C XPath 1.0 recommendation. The current XSLT context—that is, the self::node() node in the Locals window—provides the evaluation context for the XPath expression.

The following list describes which functions are supported when evaluating an XPath expression:

  • Built-in XPath functions are supported.

  • Built-in XSLT functions are not supported.

  • User-defined functions are not supported.

Note

The following procedure uses the belowAvg.xsl and books.xml files from the Walkthrough: Debug an XSLT Style Sheet topic.

To evaluate an XPath expression

  1. Insert a breakpoint at the xsl:if start tag.

  2. Click the Debug XSL button on the XML Editor toolbar.

    The debugger starts and breaks on the xsl:if tag.

  3. Right-click and select QuickWatch.

    The QuickWatch dialog box is displayed.

  4. Enter ./price/text() in the Expression field of the QuickWatch dialog box and click Reevaluate.

    The price of the current book node appears in the Value box.

  5. Change the XPath expression to ./price/text() < $bookAverage and click Reevaluate.

    The Value box shows that the XPath expression evaluates to true.

See Also

Other Resources

Debugging XSLT