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XmlTextReader.ReadAttributeValue Method

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

[Visual Basic]
Overrides Public Function ReadAttributeValue() As Boolean
[C#]
public override bool ReadAttributeValue();
[C++]
public: bool ReadAttributeValue();
[JScript]
public override function ReadAttributeValue() : Boolean;

Return Value

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.

Remarks

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.

General entities are returned as a single empty(Value is String.Empty) EntityReference node.

Example

[Visual Basic, C#, C++] The following example reads an attribute with text and entity nodes.

[Visual Basic] 
Imports System
Imports System.IO
Imports System.Xml

public class Sample

  public shared sub Main()

    Dim reader as XmlTextReader = nothing

    try
       'Create the XML fragment to be parsed.
       Dim xmlFrag as string ="<book genre='novel' misc='sale-item &h; 1987'></book>"
 
       'Create the XmlParserContext.
       Dim context as XmlParserContext 
       Dim subset as string = "<!ENTITY h 'hardcover'>"
       context = new XmlParserContext(nothing, nothing, "book", nothing, nothing, subset, "", "", XmlSpace.None)
        
       'Create the reader.
       reader = new XmlTextReader(xmlFrag, XmlNodeType.Element, context)
  
       '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)
            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
        reader.Close()
      End if
      end try
  end sub
end class 

[C#] 
using System;
using System.IO;
using System.Xml;

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

    try
    {
       //Create the XML fragment to be parsed.
       string xmlFrag ="<book genre='novel' misc='sale-item &h; 1987'></book>";
 
       //Create the XmlParserContext.
       XmlParserContext context;
       string subset = "<!ENTITY h 'hardcover'>";
       context = new XmlParserContext(null, null, "book", null, null, subset, "", "", XmlSpace.None);
        
       //Create the reader.
       reader = new XmlTextReader(xmlFrag, XmlNodeType.Element, context);
  
       //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)
            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

[C++] 
#using <mscorlib.dll>
#using <System.Xml.dll>
using namespace System;
using namespace System::IO;
using namespace System::Xml;

int main() 
{
   XmlTextReader* reader = 0;

   __try
   {
      // Create the XML fragment to be parsed.
      String* xmlFrag =S"<book genre='novel' misc='sale-item &h; 1987'></book>";

      // Create the XmlParserContext.
      XmlParserContext * context;
      String* subset = S"<!ENTITY h 'hardcover'>";
      context = new XmlParserContext(0, 0, S"book", 0, 0, subset, S"", S"", XmlSpace::None);

      // Create the reader.
      reader = new XmlTextReader(xmlFrag, XmlNodeType::Element, context);

      // Read the misc attribute. The attribute is parsed
      // into multiple text and entity reference nodes.
      reader -> MoveToContent();
      reader -> MoveToAttribute(S"misc");
      while (reader -> ReadAttributeValue())
      {
         if (reader -> NodeType == XmlNodeType::EntityReference)
            Console::WriteLine(S" {0} {1}", __box(reader -> NodeType), reader -> Name);
         else
            Console::WriteLine(S" {0} {1}", __box(reader -> NodeType), reader -> Value);
      }
   }
   __finally
   {
      if (reader != 0)
         reader -> Close();
   }
}

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, .NET Compact Framework, Common Language Infrastructure (CLI) Standard

See Also

XmlTextReader Class | XmlTextReader Members | System.Xml Namespace

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