Evaluate XPath expressions

  • Artículo

Applies to: yesVisual Studio noVisual Studio for Mac

Note

This article applies to Visual Studio 2017. If you're looking for the latest Visual Studio documentation, see Visual Studio documentation. We recommend upgrading to the latest version of Visual Studio. Download it here

You can evaluate XPath expressions by using the QuickWatch window during debugging. 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.

When evaluating an XPath expression:

  • Built-in XPath functions are supported.

  • Built-in XSLT functions and user-defined functions are not supported.

Note

XSLT debugging is only available in the Enterprise edition of Visual Studio.

Evaluate an XPath expression

The following procedure uses the below-average.xsl and books.xml files from the Walkthrough: Debug an XSLT style sheet page.

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

  2. To start debugging, choose XML > Start XSLT Debugging on the menu bar (or, press Alt+F5).

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

  3. Right-click and select QuickWatch.

    The QuickWatch window opens.

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

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

    Evaluate an XPath expression in the Quickwatch window

  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