Articolo
11/18/2011

NameTable Class

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Implements a single-threaded XmlNameTable.

Inheritance Hierarchy

System.Object
System.Xml.XmlNameTable
System.Xml.NameTable

Namespace: System.Xml
Assembly: System.Xml (in System.Xml.dll)

Syntax

'Declaration
Public Class NameTable _
    Inherits XmlNameTable

public class NameTable : XmlNameTable

The NameTable type exposes the following members.

Constructors

	Name	Description
	NameTable	Initializes a new instance of the NameTable class.

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Methods

	Name	Description
	Add(String)	Atomizes the specified string and adds it to the NameTable. (Overrides XmlNameTable.Add(String).)
	Add(array<Char[], Int32, Int32)	Atomizes the specified string and adds it to the NameTable. (Overrides XmlNameTable.Add(array<Char[], Int32, Int32).)
	Equals(Object)	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
	Get(String)	Gets the atomized string with the specified value. (Overrides XmlNameTable.Get(String).)
	Get(array<Char[], Int32, Int32)	Gets the atomized string containing the same characters as the specified range of characters in the given array. (Overrides XmlNameTable.Get(array<Char[], Int32, Int32).)
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	ToString	Returns a string that represents the current object. (Inherited from Object.)

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Remarks

The XmlReader uses the NameTable class internally to store attribute and element names. When an element or attribute name occurs multiple times in an XML document, it is stored only once in the NameTable.

The names are stored as common language runtime (CLR) object types. This enables you to do object comparisons on these strings rather than a more expensive string comparison. These string objects are referred to as atomized strings.

Examples

Dim xmlString As String = _
"<catalog>" & _
   "<book id='bk101'>" & _
      "<author>Gambardella, Matthew</author>" & _
      "<title>XML Developer's Guide</title>" & _
      "<genre>Computer</genre>" & _
      "<price>44.95</price>" & _
      "<publish_date>2000-10-01</publish_date>" & _
      "<description>An in-depth look at creating applications " & _
      "with XML.</description>" & _
   "</book>" & _
   "<book id='bk102'>" & _
      "<author>Ralls, Kim</author>" & _
      "<title>Midnight Rain</title>" & _
      "<genre>Fantasy</genre>" & _
      "<price>5.95</price>" & _
      "<publish_date>2000-12-16</publish_date>" & _
      "<description>A former architect battles corporate zombies, " & _
      "an evil sorceress, and her own childhood to become queen " & _
      "of the world.</description>" & _
   "</book>" & _
"</catalog>"


' Add the element names to the NameTable.
Dim nt As New NameTable() '
Dim book As Object = nt.Add("book")
Dim title As Object = nt.Add("title")

' Create a reader that uses the NameTable.
Dim settings As New XmlReaderSettings()
settings.NameTable = nt
Using reader As XmlReader = XmlReader.Create(New StringReader(xmlString), settings)

    While reader.Read()
        If reader.NodeType = XmlNodeType.Element Then
            ' Cache the local name to prevent multiple calls to the LocalName property.
            Dim localname As Object = reader.LocalName

            ' Do a comparison between the object references. This just compares pointers.
            If book = localname Then
            End If
            ' Add additional processing here.
            ' Do a comparison between the object references. This just compares pointers.
            If title = localname Then
            End If
        End If ' Add additional processing here.
    End While
End Using


    string xmlString =
    @"<catalog>
   <book id='bk101'>
      <author>Gambardella, Matthew</author>
      <title>XML Developer's Guide</title>
      <genre>Computer</genre>
      <price>44.95</price>
      <publish_date>2000-10-01</publish_date>
      <description>An in-depth look at creating applications 
      with XML.</description>
   </book>
   <book id='bk102'>
      <author>Ralls, Kim</author>
      <title>Midnight Rain</title>
      <genre>Fantasy</genre>
      <price>5.95</price>
      <publish_date>2000-12-16</publish_date>
      <description>A former architect battles corporate zombies, 
      an evil sorceress, and her own childhood to become queen 
      of the world.</description>
   </book>
</catalog>";

    // Add the element names to the NameTable.
    NameTable nt = new NameTable();
    object book = nt.Add("book");
    object title = nt.Add("title");

    // Create a reader that uses the NameTable.
    XmlReaderSettings settings = new XmlReaderSettings();
    settings.NameTable = nt;
    using (XmlReader reader = XmlReader.Create(new StringReader(xmlString), settings))
    {
        while (reader.Read())
        {
            if (reader.NodeType == XmlNodeType.Element)
            {
                // Cache the local name to prevent multiple calls to the LocalName property.
                object localname = reader.LocalName;

                // Do a comparison between the object references. This just compares pointers.
                if (book == localname)
                {
                    // Add additional processing here.
                }
                // Do a comparison between the object references. This just compares pointers.
                if (title == localname)
                {
                    // Add additional processing here.
                }
            }
        }
    }

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Thread Safety

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

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