XmlValidatingReader.Read-Methode

Liest den nächsten Knoten aus dem Stream.

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

Syntax

'Declaration
Public Overrides Function Read As Boolean
'Usage
Dim instance As XmlValidatingReader
Dim returnValue As Boolean

returnValue = instance.Read

public override bool Read ()

public:
virtual bool Read () override

public boolean Read ()

public override function Read () : boolean

Rückgabewert

true, wenn der nächste Knoten erfolgreich gelesen wurde, false, wenn keine weiteren zu lesenden Knoten vorhanden sind.

Hinweise

Nachdem ein Reader das erste Mal erstellt und initialisiert wurde, stehen keine Informationen zur Verfügung. Zum Lesen des ersten Knotens muss Read aufgerufen werden.

Beispiel

Im folgenden Beispiel wird eine XML-Datei gelesen, und alle Knoten werden angezeigt.

Imports System
Imports System.IO
Imports System.Xml

Public Class Sample
   Private Const filename As String = "items.xml"
   
   Public Shared Sub Main()
      Dim txtreader As XmlTextReader = Nothing
      Dim reader As XmlValidatingReader = Nothing
      
      Try
         'Load the reader with the data file and ignore all white space nodes.         
         txtreader = New XmlTextReader(filename)
         txtreader.WhitespaceHandling = WhitespaceHandling.None
         
         'Implement the validating reader over the text reader. 
         reader = New XmlValidatingReader(txtreader)
         reader.ValidationType = ValidationType.None
         
         'Parse the file and display each of the nodes.
         While reader.Read()
            Select Case reader.NodeType
               Case XmlNodeType.Element
                  Console.Write("<{0}>", reader.Name)
               Case XmlNodeType.Text
                  Console.Write(reader.Value)
               Case XmlNodeType.CDATA
                  Console.Write("<![CDATA[{0}]]>", reader.Value)
               Case XmlNodeType.ProcessingInstruction
                  Console.Write("<?{0} {1}?>", reader.Name, reader.Value)
               Case XmlNodeType.Comment
                  Console.Write("<!--{0}-->", reader.Value)
               Case XmlNodeType.XmlDeclaration
                  Console.Write("<?xml version='1.0'?>")
               Case XmlNodeType.Document
               Case XmlNodeType.DocumentType
                  Console.Write("<!DOCTYPE {0} [{1}]", reader.Name, reader.Value)
               Case XmlNodeType.EntityReference
                  Console.Write(reader.Name)
               Case XmlNodeType.EndElement
                  Console.Write("</{0}>", reader.Name)
            End Select
         End While
      
      Finally
         If Not (reader Is Nothing) Then
            reader.Close()
         End If
      End Try
   End Sub 'Main 
End Class 'Sample 

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

public class Sample
{
  private const String filename = "items.xml";

  public static void Main()
  {
     XmlTextReader txtreader = null;
     XmlValidatingReader reader = null;

     try
     {  
        //Load the reader with the data file and ignore all white space nodes.         
        txtreader = new XmlTextReader(filename);
        txtreader.WhitespaceHandling = WhitespaceHandling.None;

        //Implement the validating reader over the text reader. 
        reader = new XmlValidatingReader(txtreader);
        reader.ValidationType = ValidationType.None;

        //Parse the file and display each of the nodes.
        while (reader.Read())
        {
           switch (reader.NodeType)
           {
             case XmlNodeType.Element:
               Console.Write("<{0}>", reader.Name);
               break;
             case XmlNodeType.Text:
               Console.Write(reader.Value);
               break;
             case XmlNodeType.CDATA:
               Console.Write("<![CDATA[{0}]]>", reader.Value);
               break;
             case XmlNodeType.ProcessingInstruction:
               Console.Write("<?{0} {1}?>", reader.Name, reader.Value);
               break;
             case XmlNodeType.Comment:
               Console.Write("<!--{0}-->", reader.Value);
               break;
             case XmlNodeType.XmlDeclaration:
               Console.Write("<?xml version='1.0'?>");
               break;
             case XmlNodeType.Document:
               break;
             case XmlNodeType.DocumentType:
               Console.Write("<!DOCTYPE {0} [{1}]", reader.Name, reader.Value);
               break;
             case XmlNodeType.EntityReference:
               Console.Write(reader.Name);
               break;
             case XmlNodeType.EndElement:
               Console.Write("</{0}>", reader.Name);
               break;
           }       
        }           
     }

     finally
     {
        if (reader!=null)
          reader.Close();
     }
  }
} // End class

#using <System.Xml.dll>

using namespace System;
using namespace System::IO;
using namespace System::Xml;
int main()
{
   XmlTextReader^ txtreader = nullptr;
   XmlValidatingReader^ reader = nullptr;
   String^ filename = "items.xml";
   try
   {
      
      //Load the reader with the data file and ignore all white space nodes.         
      txtreader = gcnew XmlTextReader( filename );
      txtreader->WhitespaceHandling = WhitespaceHandling::None;
      
      //Implement the validating reader over the text reader. 
      reader = gcnew XmlValidatingReader( txtreader );
      reader->ValidationType = ValidationType::None;
      
      //Parse the file and display each of the nodes.
      while ( reader->Read() )
      {
         switch ( reader->NodeType )
         {
            case XmlNodeType::Element:
               Console::Write( "<{0}>", reader->Name );
               break;

            case XmlNodeType::Text:
               Console::Write( reader->Value );
               break;

            case XmlNodeType::CDATA:
               Console::Write( "<![CDATA[{0}]]>", reader->Value );
               break;

            case XmlNodeType::ProcessingInstruction:
               Console::Write( "<?{0} {1}?>", reader->Name, reader->Value );
               break;

            case XmlNodeType::Comment:
               Console::Write( "<!--{0}-->", reader->Value );
               break;

            case XmlNodeType::XmlDeclaration:
               Console::Write( "<?xml version='1.0'?>" );
               break;

            case XmlNodeType::Document:
               break;

            case XmlNodeType::DocumentType:
               Console::Write( "<!DOCTYPE {0} [{1}]", reader->Name, reader->Value );
               break;

            case XmlNodeType::EntityReference:
               Console::Write( reader->Name );
               break;

            case XmlNodeType::EndElement:
               Console::Write( "</{0}>", reader->Name );
               break;
         }
      }
   }
   finally
   {
      if ( reader != nullptr )
            reader->Close();
   }

}

import System.*;
import System.IO.*;
import System.Xml.*;

public class Sample
{
    private static String fileName = "items.xml";

    public static void main(String[] args)
    {
        XmlTextReader txtReader = null;
        XmlValidatingReader reader = null;

        try {
            //Load the reader with the data file and ignore all
            // white space nodes.         
            txtReader = new XmlTextReader(fileName);
            txtReader.set_WhitespaceHandling(WhitespaceHandling.None);

            //Implement the validating reader over the text reader. 
            reader = new XmlValidatingReader(txtReader);
            reader.set_ValidationType(ValidationType.None);

            //Parse the file and display each of the nodes.
            while (reader.Read()) {
                switch (reader.get_NodeType()) {
                    case XmlNodeType.Element :
                        Console.Write("<{0}>", reader.get_Name());
                        break;
                    case XmlNodeType.Text :
                        Console.Write(reader.get_Value());
                        break;
                    case XmlNodeType.CDATA :
                        Console.Write("<![CDATA[{0}]]>", reader.get_Value());
                        break;
                    case XmlNodeType.ProcessingInstruction :
                        Console.Write("<?{0} {1}?>", reader.get_Name(),
                            reader.get_Value());
                        break;
                    case XmlNodeType.Comment :
                        Console.Write("<!--{0}-->", reader.get_Value());
                        break;
                    case XmlNodeType.XmlDeclaration :
                        Console.Write("<?xml version='1.0'?>");
                        break;
                    case XmlNodeType.Document :
                        break;
                    case XmlNodeType.DocumentType :
                        Console.Write("<!DOCTYPE {0} [{1}]", reader.get_Name(),
                            reader.get_Value());
                        break;
                    case XmlNodeType.EntityReference :
                        Console.Write(reader.get_Name());
                        break;
                    case XmlNodeType.EndElement :
                        Console.Write("</{0}>", reader.get_Name());
                        break;
                }
            }
        }
        finally {
            if (reader != null) {
                reader.Close();
            }
        }
    } //main
} // End class Sample 

Im Beispiel wird die Datei items.xml als Eingabe verwendet.

<?xml version="1.0"?>
<!-- This is a sample XML document -->
<!DOCTYPE Items [<!ENTITY number "123">]>
<Items>
  <Item>Test with an entity: &number;</Item>
  <Item>test with a child element <more/> stuff</Item>
  <Item>test with a CDATA section <![CDATA[<456>]]> def</Item>
  <Item>Test with a char entity: &#65;</Item>
  <!-- Fourteen chars in this element.-->
  <Item>1234567890ABCD</Item>
</Items>

Plattformen

Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

.NET Framework unterstützt nicht alle Versionen sämtlicher Plattformen. Eine Liste der unterstützten Versionen finden Sie unter Systemanforderungen.

Versionsinformationen

.NET Framework

Unterstützt in: 2.0, 1.1, 1.0

Siehe auch

Referenz

XmlValidatingReader-Klasse
XmlValidatingReader-Member
System.Xml-Namespace

Weitere Ressourcen

Lesen von XML mit dem "XmlReader"