XmlNodeReader.ReadAttributeValue Method

Definition

Namespace:

System.Xml

Assembly:

System.Xml.ReaderWriter.dll

Source:

XmlNodeReader.cs

Parses the attribute value into one or more Text, EntityReference, or EndEntity nodes.

public:
 override bool ReadAttributeValue();

public override bool ReadAttributeValue ();

override this.ReadAttributeValue : unit -> bool

Public Overrides Function ReadAttributeValue () As Boolean

Returns

Boolean

true if there are nodes to return.

false if the reader is not positioned on an attribute node when the initial call is made or if all the attribute values have been read.

An empty attribute, such as, misc="", returns true with a single node with a value of String.Empty.

Examples

The following example reads an attribute with text and entity reference nodes.

#using <System.Xml.dll>

using namespace System;
using namespace System::IO;
using namespace System::Xml;
int main()
{
   XmlNodeReader^ reader = nullptr;
   try
   {
      
      //Create and load an XML document.
      XmlDocument^ doc = gcnew XmlDocument;
      doc->LoadXml( "<!DOCTYPE book [<!ENTITY h 'harcover'>]>"
      "<book genre='novel' misc='sale-item &h; 1987'>"
      "</book>" );
      
      //Create the reader. 
      reader = gcnew XmlNodeReader( doc );
      
      //Read the misc attribute. The attribute is parsed into multiple 
      //text and entity reference nodes.
      reader->MoveToContent();
      reader->MoveToAttribute( "misc" );
      while ( reader->ReadAttributeValue() )
      {
         if ( reader->NodeType == XmlNodeType::EntityReference )
                  
         //To expand the entity, call ResolveEntity.
         Console::WriteLine( "{0} {1}", reader->NodeType, reader->Name );
         else
                  Console::WriteLine( "{0} {1}", reader->NodeType, reader->Value );
      }
   }
   finally
   {
      if ( reader != nullptr )
            reader->Close();
   }

}

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

public class Sample
{
  public static void Main()
  {
    XmlNodeReader reader = null;

    try
    {
       //Create and load an XML document.
       XmlDocument doc = new XmlDocument();
       doc.LoadXml("<!DOCTYPE book [<!ENTITY h 'harcover'>]>" +
                   "<book genre='novel' misc='sale-item &h; 1987'>" +
                   "</book>");

       //Create the reader.
       reader = new XmlNodeReader(doc);

       //Read the misc attribute. The attribute is parsed into multiple
       //text and entity reference nodes.
       reader.MoveToContent();
       reader.MoveToAttribute("misc");
       while (reader.ReadAttributeValue()){
          if (reader.NodeType==XmlNodeType.EntityReference)
            //To expand the entity, call ResolveEntity.
            Console.WriteLine("{0} {1}", reader.NodeType, reader.Name);
          else
             Console.WriteLine("{0} {1}", reader.NodeType, reader.Value);
        }
     }
     finally
     {
        if (reader != null)
          reader.Close();
      }
  }
} // End class

Option Explicit
Option Strict

Imports System.IO
Imports System.Xml

Public Class Sample
    
    Public Shared Sub Main()
        Dim reader As XmlNodeReader = Nothing
        
        Try
            'Create and load an XML document.
            Dim doc As New XmlDocument()
            doc.LoadXml("<!DOCTYPE book [<!ENTITY h 'harcover'>]>" & _
                        "<book genre='novel' misc='sale-item &h; 1987'>" & _
                        "</book>")
            
            'Create the reader. 
            reader = New XmlNodeReader(doc)
            
            'Read the misc attribute. The attribute is parsed into multiple 
            'text and entity reference nodes.
            reader.MoveToContent()
            reader.MoveToAttribute("misc")
            While reader.ReadAttributeValue()
                If reader.NodeType = XmlNodeType.EntityReference Then
                    'To expand the entity, call ResolveEntity.
                    Console.WriteLine("{0} {1}", reader.NodeType, reader.Name)
                Else
                    Console.WriteLine("{0} {1}", reader.NodeType, reader.Value)
                End If
            End While
        Finally
            If Not (reader Is Nothing) Then
                reader.Close()
            End If
        End Try
    End Sub
End Class

Remarks

Note

In the .NET Framework 2.0, the recommended practice is to create XmlReader instances using the XmlReaderSettings class and the Create method. This allows you to take full advantage of all the new features introduced in the .NET Framework. For more information, see the Remarks section in the XmlReader reference page.

Use this method after calling MoveToAttribute to read through the text or entity reference nodes that make up the attribute value. The Depth of the attribute value nodes is one plus the depth of the attribute node; it increments and decrements by one when you step into and out of general entity references.