.NET Documentation

XmlNamespaceManager Class

Represents a manager for XML namespaces.

Namespace: System.Xml

Assembly: System.Xml.dll

Summary

The XmlNamespaceManager class is used to manage XML namespaces within an XML document. It allows you to add, remove, and resolve namespace prefixes and URIs. This is crucial for parsing and processing XML documents that utilize namespaces, ensuring that prefixes are correctly associated with their respective URIs.

Constructor

Public Constructors

XmlNamespaceManager(XmlNameTable nameTable)

Initializes a new instance of the XmlNamespaceManager class with the specified XmlNameTable.

Parameters:

Name Type Description
nameTable XmlNameTable An XmlNameTable to store the names in.

Properties

Public Properties

NameTable

Gets the XmlNameTable used by this XmlNamespaceManager.

Property Value: XmlNameTable. The XmlNameTable associated with this XmlNamespaceManager.

Methods

Public Methods

AddNamespace(string prefix, string uri)

Adds a namespace declaration to the XmlNamespaceManager.

Parameters:

Name Type Description
prefix string The prefix of the namespace to add.
uri string The URI of the namespace to add.

RemoveNamespace(string prefix, string uri)

Removes a namespace declaration from the XmlNamespaceManager.

Parameters:

Name Type Description
prefix string The prefix of the namespace to remove.
uri string The URI of the namespace to remove.

LookupNamespace(string prefix)

Looks up the given namespace prefix and returns the corresponding URI.

Parameters:

Name Type Description
prefix string The namespace prefix to look up.

Returns: string. The URI for the specified prefix, or null if the prefix is not found.

LookupPrefix(string uri)

Looks up the given namespace URI and returns the corresponding prefix.

Parameters:

Name Type Description
uri string The namespace URI to look up.

Returns: string. The prefix for the specified URI, or null if the URI is not found.

PushScope()

Pushes a new scope onto the namespace manager stack. This is useful for hierarchical processing of XML elements.

PopScope()

Pops the current scope from the namespace manager stack. This reverts to the previous namespace declarations.

HasNamespace(string prefix, string uri)

Checks if the given namespace prefix and URI combination exists in the current scope.

Parameters:

Name Type Description
prefix string The namespace prefix to check.
uri string The namespace URI to check.

Returns: bool. true if the namespace exists; otherwise, false.

Usage Example

The following example demonstrates how to use XmlNamespaceManager to manage namespaces when processing an XML document.


using System;
using System.Xml;

public class Example
{
    public static void Main(string[] args)
    {
        string xmlString = @"

  
    Gambardella, Matthew
    XML Developer's Guide
    Computer
  
";

        XmlDocument doc = new XmlDocument();
        doc.LoadXml(xmlString);

        // Create an XmlNamespaceManager
        XmlNamespaceManager nsManager = new XmlNamespaceManager(doc.NameTable);

        // Add namespaces to the manager
        nsManager.AddNamespace("bk", "urn:samples:bookstore");
        nsManager.AddNamespace("ex", "urn:samples:examples");

        // Select nodes using XPath with namespaces
        XmlNodeList bookNodes = doc.SelectNodes("//bk:book", nsManager);

        foreach (XmlNode bookNode in bookNodes)
        {
            XmlNode titleNode = bookNode.SelectSingleNode("bk:title", nsManager);
            XmlNode genreNode = bookNode.SelectSingleNode("ex:genre", nsManager);

            if (titleNode != null && genreNode != null)
            {
                Console.WriteLine($"Book Title: {titleNode.InnerText}");
                Console.WriteLine($"Genre: {genreNode.InnerText}");
            }
        }

        // Look up prefixes and URIs
        Console.WriteLine($""\nLookup: bk -> {nsManager.LookupNamespace(""bk"")}"");
        Console.WriteLine($""Lookup: urn:samples:bookstore -> {nsManager.LookupPrefix(""urn:samples:bookstore"")}"");
    }
}

See Also