XmlNodeReader.HasValue Property

Reference

Definition

Namespace:: System.Xml

Assemblies:: netstandard.dll, System.Xml.ReaderWriter.dll

Assembly:: System.Xml.ReaderWriter.dll

Assembly:: System.Xml.dll

Assembly:: netstandard.dll

Source:: XmlNodeReader.cs

Source:: XmlNodeReader.cs

Source:: XmlNodeReader.cs

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Gets a value indicating whether the current node can have a Value.

public:
 virtual property bool HasValue { bool get(); };

public override bool HasValue { get; }

member this.HasValue : bool

Public Overrides ReadOnly Property HasValue As Boolean

Property Value

Boolean

true if the node on which the reader is currently positioned can have a Value; otherwise, false.

Examples

The following example displays the value for every node which can have a value.

#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 XmlDocument.
      XmlDocument^ doc = gcnew XmlDocument;
      doc->LoadXml( "<?xml version='1.0' ?>"
      "<!DOCTYPE book [<!ENTITY h 'hardcover'>]>"
      "<book>"
      "<title>Pride And Prejudice</title>"
      "<misc>&h;</misc>"
      "</book>" );
      reader = gcnew XmlNodeReader( doc );
      
      // Parse the file and display each node.
      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 );
      }
   }
   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 XmlDocument.
        XmlDocument doc = new XmlDocument();
        doc.LoadXml("<?xml version='1.0' ?>" +
                    "<!DOCTYPE book [<!ENTITY h 'hardcover'>]>" +
                    "<book>" +
                    "<title>Pride And Prejudice</title>" +
                    "<misc>&h;</misc>" +
                    "</book>");

        reader = new XmlNodeReader(doc);

        // Parse the file and display each node.
        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);
         }
     }

     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 XmlDocument.
            Dim doc As New XmlDocument()
            doc.LoadXml("<?xml version='1.0' ?>" & _
                        "<!DOCTYPE book [<!ENTITY h 'hardcover'>]>" & _
                        "<book>" & _
                        "<title>Pride And Prejudice</title>" & _
                        "<misc>&h;</misc>" & _
                        "</book>")
            
            reader = New XmlNodeReader(doc)
            
            'Parse the file and display each node.
            While reader.Read()
                If reader.HasValue Then
                    Console.WriteLine("({0})  {1}={2}", reader.NodeType, reader.Name, reader.Value)
                Else
                    Console.WriteLine("({0}) {1}", reader.NodeType, reader.Name)
                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.

The following table lists node types that have a value to return.

Node Type	Value
`Attribute`	The value of the attribute.
`CDATA`	The content of the CDATA section.
`Comment`	The content of the comment.
`DocumentType`	The internal subset.
`ProcessingInstruction`	The entire content, excluding the target.
`SignificantWhitespace`	The white space between markup in a mixed content model.
`Text`	The content of the text node.
`Whitespace`	The white space between markup.
`XmlDeclaration`	The content of the declaration.

Applies to

Product	Versions
.NET	Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10
.NET Framework	1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard	2.0, 2.1

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