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SeekableXPathNavigator Class

Provides read-only, random access to data contained in XML documents and enables efficient querying for specified nodes.

Namespace:  System.ServiceModel.Dispatcher
Assembly:  System.ServiceModel (in System.ServiceModel.dll)

public abstract class SeekableXPathNavigator extends XPathNavigator

The SOAP messages passed between parts of the Windows Communication Foundation (WCF) system are handled by various components of the system that must inspect these messages to determine what actions to take in processing them. The XPath engine is a component that queries messages for this purpose and it requires a navigator to read SOAP messages and other XML documents. A navigator provides a cursor that moves from node to node tracking where the XML document is actually being read.

The XPath engine works with a SeekableXPathNavigator, which extends the XPathNavigator class by adding a CurrentPosition property. This property allows positions within the XML document to be saved and loaded quickly without having to clone the navigator, an expensive memory allocation that the XPathNavigator requires for such an operation. The XPath engine must frequently record the position of the cursor in the course of executing queries on XML documents, so the SeekableXPathNavigator provides an important optimization for message processing.

Note that the value of the CurrentPosition property is implementation-specific and may not map to node position or character position. Its value is only meaningful to the SeekableXPathNavigator implementation (and instance) that supplied it.


Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0