XmlValidatingReader.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:: XmlValidatingReader.cs

Source:: XmlValidatingReader.cs

Source:: XmlValidatingReader.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 other than String.Empty.

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 reads in XML with various data types and displays each of the nodes.

#using <System.Xml.dll>

using namespace System;
using namespace System::IO;
using namespace System::Xml;
int main()
{
   
   //Create the validating reader.
   XmlTextReader^ txtreader = gcnew XmlTextReader( "book1.xml" );
   txtreader->WhitespaceHandling = WhitespaceHandling::None;
   XmlValidatingReader^ reader = gcnew XmlValidatingReader( txtreader );
   reader->ValidationType = ValidationType::None;
   
   //Parse the file and each node and its value.
   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 );
   }

   
   //Close the reader.
   reader->Close();
}

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

public class Sample
{

  public static void Main()
  {

    //Create the validating reader.
    XmlTextReader txtreader = new XmlTextReader("book1.xml");
    txtreader.WhitespaceHandling = WhitespaceHandling.None;
    XmlValidatingReader reader = new XmlValidatingReader(txtreader);
    reader.ValidationType = ValidationType.None;

    //Parse the file and each node and its value.
    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);
    }

    //Close the reader.
    reader.Close();
  }
} // End class

Imports System.IO
Imports System.Xml

public class Sample

  public shared sub  Main()
  
    'Create the validating reader.
    Dim txtreader as XmlTextReader = new XmlTextReader("book1.xml")
    txtreader.WhitespaceHandling = WhitespaceHandling.None
    Dim reader as XmlValidatingReader = new XmlValidatingReader(txtreader)
    reader.ValidationType = ValidationType.None

    'Parse the file and each node and its value.
    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

    'Close the reader.
    reader.Close()
    
  end sub
end class

Remarks

Anteckning

The XmlValidatingReader class is obsolete in .NET Framework 2.0. You can create a validating XmlReader instance by using the XmlReaderSettings class and the Create method. For more information, see the Remarks section of 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

Produkt	Versioner
.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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