XPath is a W3C specification for locating nodes in an XML document. It provides an expression syntax that can determine a node based on its type, location, and relation to other nodes in a document. XPath is generally not useful alone, but works in conjunction with other tools, especially XSLT. Figure 45-1 shows the types in this namespace.
System.Xml.XPath provides types that evaluate expressions
and match nodes in XML documents.
is a document object designed to provide fast document navigation through
XPath, and is used by the
System.Xml.Xsl classes for
XPathNavigator is the core
entry point for doing XPath expressions; it is abstract, allowing for more than
just XML documents to be XPath-navigated. For example, an ADO.NET provider could,
if it desired, implement the
IXPathNavigable interface and
XPathNavigator that translated XPath queries
into a SQL SELECT statement. (See Aaron Skonnard’s MSDN Magazine article
“Writing XML Providers for Microsoft .NET” for more details about using
XML-based technologies over data sources other than XML documents.)
Figure 45-1. The System.Xml.XPath namespace