System.Xml.XmlNamespaceManager Class

Summary

Resolves, adds and removes namespaces to a collection and provide scope management for these namespaces. This class is used by the XsltContext and XmlReader classes.

C# Syntax:

public class XmlNamespaceManager : IEnumerable

XmlNamespaceManager stores prefixes and namespaces as strings.

System.Xml Namespace

System.Xml.XmlNamespaceManager Member List:

Public Constructors

ctor #1

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

Public Properties

DefaultNamespace	Read-only Gets the namespace URI for the default namespace.
NameTable	Read-only Gets the XmlNameTable associated with this object.

Public Methods

AddNamespace	Adds the given namespace to the collection.
Equals (inherited from System.Object)	See base class member description: System.Object.Equals Derived from System.Object, the primary base class for all objects.
GetEnumerator	Provides support for the "foreach" style iteration over the collection of namespaces in the XmlNamespaceManager.
GetHashCode (inherited from System.Object)	See base class member description: System.Object.GetHashCode Derived from System.Object, the primary base class for all objects.
GetType (inherited from System.Object)	See base class member description: System.Object.GetType Derived from System.Object, the primary base class for all objects.
HasNamespace	Gets a value indicating whether the supplied prefix has a namespace defined for the current pushed scope.
LookupNamespace	Gets the namespace URI for the specified prefix.
LookupPrefix	Finds the prefix declared for the given namespace URI.
PopScope	Pops a namespace scope off the stack.
PushScope	Pushes a namespace scope onto the stack.
RemoveNamespace	Removes the given namespace for the given prefix.
ToString (inherited from System.Object)	See base class member description: System.Object.ToString Derived from System.Object, the primary base class for all objects.

Protected Methods

Finalize (inherited from System.Object)	See base class member description: System.Object.Finalize Derived from System.Object, the primary base class for all objects.
MemberwiseClone (inherited from System.Object)	See base class member description: System.Object.MemberwiseClone Derived from System.Object, the primary base class for all objects.

Hierarchy:

• System.Object
• System.Xml.XmlNamespaceManager
  • System.Xml.Xsl.XsltContext

System.Xml.XmlNamespaceManager Member Details

Summary

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

C# Syntax:

public XmlNamespaceManager(    XmlNameTable nameTable );

nameTable

The XmlNameTable to use.

Exceptions

Exception Type	Condition
NullReferenceException	null is passed to the constructor

The name table is used to look up prefixes and namespaces. An existing name table with pre-atomized strings can be specified in the constructor. There are several advantages in doing so. If a XmlReader's name table is used, after each read any namespace and prefix strings pushed into the name table can be re-used by XmlNamespaceManager. Also, because XmlNamespaceManager is used internally by the XmlReader, it can take advantage of the reader's ability to atomize strings.

For more information on atomized strings, see XmlNameTable.

Note If you specify an existing name table, any namespaces in the name table are not automatically added to XmlNamespaceManager. You must use XmlNamespaceManager.AddNamespace and XmlNamespaceManager.RemoveNamespace to add or remove namespaces.

The following example creates an XmlNamespaceManager using the name table of the reader.

        XmlTextReader reader = new XmlTextReader("myfile.xml");
        XmlNamespaceManager nsmanager = new XmlNamespaceManager(reader.NameTable);
        nsmanager.AddNamespace("msbooks", "www.microsoft.com/books");
        nsmanager.PushScope();
        nsmanager.AddNamespace("msstore", "www.microsoft.com/store");
        while (reader.Read())
        {
            Console.WriteLine("Reader Prefix:{0}", reader.Prefix);
            Console.WriteLine("XmlNamespaceManager Prefix:{0}",
                              nsmanager.LookupPrefix(nsmanager.NameTable.Get(reader.NamespaceURI)));
        }

    

Return to top

Summary

Gets the namespace URI for the default namespace.

C# Syntax:

public virtual string DefaultNamespace {get;}

This method is equivalent to calling LookupNamespace(String.Empty).

The following example displays the default namespace, if one exists.

if (nsmgr.HasNamespace(String.Empty))
  Console.WriteLine(nsmgr.DefaultNamespace);

    

Return to top

Summary

Gets the XmlNameTable associated with this object.

C# Syntax:

public XmlNameTable NameTable {get;}

The name table is used to look up prefixes and namespace URIs.

Return to top

Summary

Adds the given namespace to the collection.

C# Syntax:

public virtual void AddNamespace(    string prefix,    string uri );

prefix

The prefix to associate with the namespace being added. Use String.Empty to add a default namespace.

uri

The namespace to add.

Exceptions

Exception Type	Condition
InvalidOperationException	The value for prefix is "xmlns".

XmlNamespaceManager does not check prefix and uri for conformance.

XmlReader checks names, including prefixes and namespaces, to ensure they are valid XML names according to the W3C specification.XmlNamespaceManager is used internally by XmlReader, so to avoid a duplication of efforts, XmlNamespaceManager assumes all prefixes and namespaces are valid.

If the prefix and namespace already exists within the current scope, it will replace the existing prefix/namespace combination. The same prefix and namespace combination can exist across different scopes.

The following prefix/namespace pairs are added by default to the XmlNamespaceManager. They can be determined at any scope.

Prefix	Namespace
xmlns	http://www.w3.org/2000/xmlns/ (the xmlns prefix namespace)
xml	http://www.w3.org/XML/1998/namespace (The XML namespace)
String.Empty	String.Empty (The empty namespace). This value can be reassigned a different prefix. For example, xmlns="" defines the default namespace to be the empty namespace

The following example uses XmlNamespaceManager to resolve namespaces in an XML fragment.

using System;
using System.IO;
using System.Xml;

//Reads an XML fragment

public class Sample
{
  public static void Main()
  {
    try
    {
      //The string containing the XML to read
      String xmlFrag="<book>" +
                     "<title>Pride And Prejudice</title>" +
                     "<author>" +
                     "<first-name>Jane</first-name>" +
                     "<last-name>Austen</last-name>" +
                     "</author>" +
                     "<curr:price>19.95</curr:price>" +
                     "<misc>&h;</misc>" +
                     "</book>";  

      ReadSample sample = new ReadSample(xmlFrag);
      sample.ReadIt();
            
    }
    catch (Exception e)
    {
      Console.WriteLine ("Exception: {0}", e.ToString());
    }

  }

} // End class

//Reads an XML fragment 

public class ReadSample
{
   XmlValidatingReader reader = null;
   
   public ReadSample(String xmlFrag)
   {

     //create an XmlNamespaceManager to resolve namespaces
     NameTable nt = new NameTable();
     XmlNamespaceManager nsmgr = new XmlNamespaceManager(nt);
     nsmgr.AddNamespace(String.Empty, "urn:samples"); //default namespace
     nsmgr.AddNamespace("curr", "urn:samples:dollar");

     //Create an XmlParserContext.  The XmlParserContext contains all the information
     //required to parse the XML fragment, including the entity information
     XmlParserContext context;
     String subset="<!ENTITY h 'hardcover'>";
     context=new XmlParserContext(nt, nsmgr, "book", null, null, subset, null, null, XmlSpace.None);

     //create the reader
     reader = new XmlValidatingReader(xmlFrag, XmlNodeType.Element, context);

   }

   //Read the XML fragment 
   public void ReadIt()
   {
    try
    {
      while(reader.Read())
      {
        if (reader.HasValue)
          Console.WriteLine("{0} [{1}] = {2}",reader.NodeType, reader.Name, reader.Value);
        else
          Console.WriteLine("{0} [{1}]",reader.NodeType, reader.Name);
      }

    }
    catch (Exception e)
    {
      Console.WriteLine ("Exception: {0}", e.ToString());
    }
   }
 
} //End class

    

Return to top

Inherited
See base class member description: System.Object.Equals

C# Syntax:

public virtual bool Equals(    object obj );

For more information on members inherited from System.Object click on the link above.

Return to top

Inherited
See base class member description: System.Object.Finalize

C# Syntax:

~XmlNamespaceManager();

For more information on members inherited from System.Object click on the link above.

Return to top

Summary

Provides support for the "foreach" style iteration over the collection of namespaces in the XmlNamespaceManager.

C# Syntax:

public virtual IEnumerator GetEnumerator();

Return Value:

An IEnumerator.

Implements:

IEnumerable.GetEnumerator

Return to top

Inherited
See base class member description: System.Object.GetHashCode

C# Syntax:

public virtual int GetHashCode();

For more information on members inherited from System.Object click on the link above.

Return to top

Inherited
See base class member description: System.Object.GetType

C# Syntax:

public Type GetType();

For more information on members inherited from System.Object click on the link above.

Return to top

Summary

Gets a value indicating whether the supplied prefix has a namespace defined for the current pushed scope.

C# Syntax:

public virtual bool HasNamespace(    string prefix );

prefix

The prefix of the namespace you want to find.

Return Value:

true if there is a namespace defined; otherwise, false.

To determine whether there is a default empty namespace defined, set prefix to String.Empty. If the method returns true, this indicates that there is a default namespace defined in current scope. Returning false indicates that no default namespace is defined.Note: xmlns:x= "" is illegal according to W3C Namespaces in XML recommendation.

The following example displays the default namespace, if one it exists.

if (nsmgr.HasNamespace(String.Empty))
  Console.WriteLine(nsmgr.DefaultNamespace);

    

Return to top

Summary

Gets the namespace URI for the specified prefix.

C# Syntax:

public virtual string LookupNamespace(    string prefix );

prefix

The prefix whose namespace URI you want to resolve. To match the default namespace, pass String.Empty.

Return Value:

Returns the namespace URI for prefix or null if there is no mapped namespace. The returned string is atomized.

For more information on atomized strings, see XmlNameTable.

The following example adds prefix/namespace pairs to the XmlNamespaceManager and then displays all the pairs in the collection.

using System;
using System.IO;
using System.Xml;


public class Sample
{
  public static void Main()
  {
    Sample test = new Sample();
  }
  public Sample()
  {
    //Create the XmlNamespaceManager.
    NameTable nt = new NameTable();
    XmlNamespaceManager nsmgr = new XmlNamespaceManager(nt);

    //Add prefix/namespace pairs to the XmlNamespaceManager.
    nsmgr.AddNamespace("", "www.wideworldimporters.com"); //Adds a default namespace.
    nsmgr.AddNamespace("europe", "www.wideworldimporters.com/europe");
    nsmgr.PushScope();  //Pushes a namespace scope on the stack.
    nsmgr.AddNamespace("", "www.lucernepublishing.com"); //Adds another default namespace.
    nsmgr.AddNamespace("partners", "www.lucernepublishing.com/partners");

    Console.WriteLine("Show all the prefix/namespace pairs in the XmlNamespaceManager...");
    ShowAllNamespaces(nsmgr);
  }

  private void ShowAllNamespaces(XmlNamespaceManager nsmgr)
  {
    do{
       foreach (String prefix in nsmgr)
       {
        Console.WriteLine("Prefix={0}, Namespace={1}", prefix,nsmgr.LookupNamespace(prefix));
       } 
    }
    while (nsmgr.PopScope());
  }
}

    

Return to top

Summary

Finds the prefix declared for the given namespace URI.

C# Syntax:

public virtual string LookupPrefix(    string uri );

uri

The namespace to resolve for the prefix.

Return Value:

The matching prefix. If there is no mapped prefix, the method returns String.Empty. If a null value is supplied then null is returned.

This method finds the mapped prefix by walking the stack (that is it looks globally). The supplied string must be atomized for the lookup to succeed. In other words the supplied string object must exist in the XmlNamespaceManager's XmlNamespaceManager.NameTable.

The returned string is also atomized. For more information on atomized strings, see XmlNameTable.

The following example removes a namespace from the namespace manager.

String prefix = nsmgr.LookupPrefix("www.wideworldimporters.com/europe");
nsmgr.RemoveNamespace(prefix, "www.wideworldimporters.com/europe");

    

Return to top

Inherited
See base class member description: System.Object.MemberwiseClone

C# Syntax:

protected object MemberwiseClone();

For more information on members inherited from System.Object click on the link above.

Return to top

Summary

Pops a namespace scope off the stack.

C# Syntax:

public virtual bool PopScope();

Return Value:

true if there are namespace scopes left on the stack; false if there are no more namespaces to pop.

When you call this method, all namespaces which were added to XmlNamespaceManager (by calling XmlNamespaceManager.AddNamespace) since the last call to PopScope, are removed.

The following example adds prefix/namespace pairs to the XmlNamespaceManager and then displays all the pairs in the collection.

using System;
using System.IO;
using System.Xml;


public class Sample
{
  public static void Main()
  {
    Sample test = new Sample();
  }
  public Sample()
  {
    //Create the XmlNamespaceManager.
    NameTable nt = new NameTable();
    XmlNamespaceManager nsmgr = new XmlNamespaceManager(nt);

    //Add prefix/namespace pairs to the XmlNamespaceManager.
    nsmgr.AddNamespace("", "www.wideworldimporters.com"); //Adds a default namespace.
    nsmgr.AddNamespace("europe", "www.wideworldimporters.com/europe");
    nsmgr.PushScope();  //Pushes a namespace scope on the stack.
    nsmgr.AddNamespace("", "www.lucernepublishing.com"); //Adds another default namespace.
    nsmgr.AddNamespace("partners", "www.lucernepublishing.com/partners");

    Console.WriteLine("Show all the prefix/namespace pairs in the XmlNamespaceManager...");
    ShowAllNamespaces(nsmgr);
  }

  private void ShowAllNamespaces(XmlNamespaceManager nsmgr)
  {
    do{
       foreach (String prefix in nsmgr)
       {
        Console.WriteLine("Prefix={0}, Namespace={1}", prefix,nsmgr.LookupNamespace(prefix));
       } 
    }
    while (nsmgr.PopScope());
  }
}

    

Return to top

Summary

Pushes a namespace scope onto the stack.

C# Syntax:

public virtual void PushScope();

After a call to this method all namespaces, which are added to XmlNamespaceManager (by calling XmlNamespaceManager.AddNamespace), belong to the pushed namespace scope.

The following example adds prefix/namespace pairs to the XmlNamespaceManager and then displays all the pairs in the collection.

using System;
using System.IO;
using System.Xml;


public class Sample
{
  public static void Main()
  {
    Sample test = new Sample();
  }
  public Sample()
  {
    //Create the XmlNamespaceManager.
    NameTable nt = new NameTable();
    XmlNamespaceManager nsmgr = new XmlNamespaceManager(nt);

    //Add prefix/namespace pairs to the XmlNamespaceManager.
    nsmgr.AddNamespace("", "www.wideworldimporters.com"); //Adds a default namespace.
    nsmgr.AddNamespace("europe", "www.wideworldimporters.com/europe");
    nsmgr.PushScope();  //Pushes a namespace scope on the stack.
    nsmgr.AddNamespace("", "www.lucernepublishing.com"); //Adds another default namespace.
    nsmgr.AddNamespace("partners", "www.lucernepublishing.com/partners");

    Console.WriteLine("Show all the prefix/namespace pairs in the XmlNamespaceManager...");
    ShowAllNamespaces(nsmgr);
  }

  private void ShowAllNamespaces(XmlNamespaceManager nsmgr)
  {
    do{
       foreach (String prefix in nsmgr)
       {
        Console.WriteLine("Prefix={0}, Namespace={1}", prefix,nsmgr.LookupNamespace(prefix));
       } 
    }
    while (nsmgr.PopScope());
  }
}

    

Return to top

Summary

Removes the given namespace for the given prefix.

C# Syntax:

public virtual void RemoveNamespace(    string prefix,    string uri );

prefix

The prefix for the namespace

uri

The namespace to remove for the given prefix. The namespace removed is from the current namespace scope. Namespaces outside the current scope are ignored. Exceptions are never thrown.

Return to top

Inherited
See base class member description: System.Object.ToString

C# Syntax:

public virtual string ToString();

For more information on members inherited from System.Object click on the link above.

Return to top

Top of page