XmlElementAttributes-Klasse

Stellt eine Auflistung von XmlElementAttribute-Objekten dar, die vom XmlSerializer zum Überschreiben des Standardverfahrens für die Serialisierung einer Klasse verwendet wird.

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

Syntax

'Declaration
Public Class XmlElementAttributes
    Inherits CollectionBase
'Usage
Dim instance As XmlElementAttributes

public class XmlElementAttributes : CollectionBase

public ref class XmlElementAttributes : public CollectionBase

public class XmlElementAttributes extends CollectionBase

public class XmlElementAttributes extends CollectionBase

Hinweise

Das XmlElementAttributes wird von der XmlElements-Eigenschaft der XmlAttributes-Klasse zurückgegeben. Mithilfe der XmlAttributeOverrides-Klasse und der XmlAttributes-Klasse können Sie das Standardverfahren überschreiben, mit dem XmlSerializer eine Klasse serialisiert.

Beispiel

Im folgenden Beispiel wird die Transportation-Klasse serialisiert. Diese enthält das einzelne Feld Vehicles, das eine ArrayList zurückgibt. Im Beispiel werden zuerst zwei Instanzen der XmlElementAttribute-Klasse auf das Vehicles-Feld angewendet. Diese gibt die Typen der Objekte an, die XmlSerializer in das Array einfügen kann. Im Beispiel werden dann zwei XmlElementAttribute-Objekte erstellt, um das Verhalten der auf die Vehicles-Eigenschaft angewendeten Attribute zu überschreiben. Die beiden überschreibenden Objekte werden der XmlElementAttributes-Auflistung eines XmlAttributes hinzugefügt. Zuletzt wird im Beispiel ein XmlAttributes einem XmlAttributeOverrides hinzugefügt. Somit wird es dem XmlSerializer ermöglicht, die neuen Objekttypen in die ArrayList einzufügen, die vom Vehicles-Feld zurückgegeben wird.

Imports System
Imports System.IO
Imports System.Xml.Serialization
Imports System.Collections
Imports System.Xml


Public Class Transportation
    ' Override these two XmlElementAttributes.
    <XmlElement(GetType(Car)), _
     XmlElement(GetType(Plane))> _
    Public Vehicles As ArrayList
End Class

Public Class Car
    Public Name As String
End Class

Public Class Plane
    Public Name As String
End Class

Public Class Truck
    Public Name As String
End Class

Public Class Train
    Public Name As String
End Class

Public Class Test
    
    Public Shared Sub Main()
        Dim t As New Test()
        t.SerializeObject("OverrideElement.xml")
    End Sub
    
    
    Public Function CreateOverrider() As XmlSerializer
        ' Create XmlAtrributes and XmlAttributeOverrides instances. 
        Dim attrs As New XmlAttributes()
        
        Dim xOver As New XmlAttributeOverrides()
        
        ' Create an XmlElementAttributes object to override
        ' one of the attributes applied to the Vehicles property. 
        Dim xElement1 As New XmlElementAttribute(GetType(Truck))
        ' Add the XmlElementAttribute to the collection.
        attrs.XmlElements.Add(xElement1)
        
        ' Create a second XmlElementAttribute and
        ' add it to the collection. 
        Dim xElement2 As New XmlElementAttribute(GetType(Train))
        attrs.XmlElements.Add(xElement2)
        
        ' Add the XmlAttributes to the XmlAttributeOverrides,
        ' specifying the member to override. 
        xOver.Add(GetType(Transportation), "Vehicles", attrs)
        
        ' Create the XmlSerializer, and return it.
        Dim xSer As New XmlSerializer(GetType(Transportation), xOver)
        Return xSer
    End Function
    
    
    Public Sub SerializeObject(ByVal filename As String)
        ' Create an XmlSerializer instance.
        Dim xSer As XmlSerializer = CreateOverrider()
        
        ' Create the object.
        Dim myTransportation As New Transportation()
        
        ' Create two new, overriding objects that can be
        ' inserted into the Vehicles array. 
        myTransportation.Vehicles = New ArrayList()
        Dim myTruck As New Truck()
        myTruck.Name = "MyTruck"
        
        Dim myTrain As New Train()
        myTrain.Name = "MyTrain"
        
        myTransportation.Vehicles.Add(myTruck)
        myTransportation.Vehicles.Add(myTrain)
        
        Dim writer As New StreamWriter(filename)
        xSer.Serialize(writer, myTransportation)
    End Sub
End Class

using System;
using System.IO;
using System.Xml.Serialization;
using System.Collections;
using System.Xml;

public class Transportation
{
   // Override these two XmlElementAttributes.
   [XmlElement(typeof(Car)),
   XmlElement(typeof(Plane))]
   public ArrayList Vehicles;
}

public class Car
{
   public string Name;
}

public class Plane
{
   public string Name;
}

public class Truck
{
   public string Name;
}

public class Train
{
   public string Name;
}

public class Test
{
   public static void Main()
   {
      Test t = new Test();
      t.SerializeObject("OverrideElement.xml");
   }

   public XmlSerializer CreateOverrider()
   {
      // Create XmlAtrributes and XmlAttributeOverrides instances. 
   
      XmlAttributes attrs = new XmlAttributes();

      XmlAttributeOverrides xOver = 
      new XmlAttributeOverrides();
      
      /* Create an XmlElementAttributes object to override 
      one of the attributes applied to the Vehicles property. */
      XmlElementAttribute xElement1 = 
      new XmlElementAttribute(typeof(Truck));
      // Add the XmlElementAttribute to the collection.
      attrs.XmlElements.Add(xElement1);

      /* Create a second XmlElementAttribute and 
      add it to the collection. */
      XmlElementAttribute xElement2 = 
      new XmlElementAttribute(typeof(Train));
      attrs.XmlElements.Add(xElement2);

      /* Add the XmlAttributes to the XmlAttributeOverrides,
      specifying the member to override. */
      xOver.Add(typeof(Transportation), "Vehicles", attrs);
      
      // Create the XmlSerializer, and return it.
      XmlSerializer xSer = new XmlSerializer
      (typeof(Transportation), xOver);
      return xSer;
   }

   public void SerializeObject(string filename)
   {
      // Create an XmlSerializer instance.
      XmlSerializer xSer = CreateOverrider();

      // Create the object.
      Transportation myTransportation = 
      new Transportation();

      /* Create two new, overriding objects that can be
      inserted into the Vehicles array. */
      myTransportation.Vehicles = new ArrayList();
      Truck myTruck = new Truck();
      myTruck.Name = "MyTruck";

      Train myTrain = new Train();
      myTrain.Name = "MyTrain";

      myTransportation.Vehicles.Add(myTruck);
      myTransportation.Vehicles.Add(myTrain);

      TextWriter writer = new StreamWriter(filename);
      xSer.Serialize(writer, myTransportation);
   }
}

#using <System.Xml.dll>
#using <System.dll>

using namespace System;
using namespace System::IO;
using namespace System::Xml::Serialization;
using namespace System::Collections;
using namespace System::Xml;

public ref class Car
{
public:
   String^ Name;
};

public ref class Plane
{
public:
   String^ Name;
};

public ref class Truck
{
public:
   String^ Name;
};

public ref class Train
{
public:
   String^ Name;
};

public ref class Transportation
{
public:

   // Override these two XmlElementAttributes.

   [XmlElement(Car::typeid),
   XmlElement(Plane::typeid)]
   ArrayList^ Vehicles;
};

XmlSerializer^ CreateOverrider()
{
   // Create XmlAtrributes and XmlAttributeOverrides instances. 
   XmlAttributes^ attrs = gcnew XmlAttributes;
   XmlAttributeOverrides^ xOver = gcnew XmlAttributeOverrides;

   /* Create an XmlElementAttributes object to override 
      one of the attributes applied to the Vehicles property. */
   XmlElementAttribute^ xElement1 = gcnew XmlElementAttribute( Truck::typeid );

   // Add the XmlElementAttribute to the collection.
   attrs->XmlElements->Add( xElement1 );

   /* Create a second XmlElementAttribute and 
      add it to the collection. */
   XmlElementAttribute^ xElement2 = gcnew XmlElementAttribute( Train::typeid );
   attrs->XmlElements->Add( xElement2 );

   /* Add the XmlAttributes to the XmlAttributeOverrides,
      specifying the member to override. */
   xOver->Add( Transportation::typeid, "Vehicles", attrs );

   // Create the XmlSerializer, and return it.
   XmlSerializer^ xSer = gcnew XmlSerializer( Transportation::typeid,xOver );
   return xSer;
}

void SerializeObject( String^ filename )
{
   // Create an XmlSerializer instance.
   XmlSerializer^ xSer = CreateOverrider();

   // Create the object.
   Transportation^ myTransportation = gcnew Transportation;

   /* Create two new, overriding objects that can be
      inserted into the Vehicles array. */
   myTransportation->Vehicles = gcnew ArrayList;
   Truck^ myTruck = gcnew Truck;
   myTruck->Name = "MyTruck";
   Train^ myTrain = gcnew Train;
   myTrain->Name = "MyTrain";
   myTransportation->Vehicles->Add( myTruck );
   myTransportation->Vehicles->Add( myTrain );
   TextWriter^ writer = gcnew StreamWriter( filename );
   xSer->Serialize( writer, myTransportation );
}

int main()
{
   SerializeObject( "OverrideElement.xml" );
}

import System.*;
import System.IO.*;
import System.Xml.Serialization.*;
import System.Collections.*;
import System.Xml.*;

public class Transportation
{
    // Override these two XmlElementAttributes.
    /** @attribute XmlElement(Car.class)
        @attribute XmlElement(Plane.class)
     */
    public ArrayList vehicles;
} //Transportation

public class Car
{
    public String name;
} //Car

public class Plane
{
    public String name;
} //Plane

public class Truck
{
    public String name;
} //Truck

public class Train
{
    public String name;
} //Train

public class Test
{
    public static void main(String[] args)
    {
        Test t = new Test();
        t.SerializeObject("OverrideElement.xml");
    } //main

    public XmlSerializer CreateOverrider()
    {
        // Create XmlAtrributes and XmlAttributeOverrides instances. 
        XmlAttributes attrs = new XmlAttributes();
        XmlAttributeOverrides xOver = new XmlAttributeOverrides();

        /* Create an XmlElementAttributes object to override 
           one of the attributes applied to the Vehicles property. */
        XmlElementAttribute xElement1 =
            new XmlElementAttribute(Truck.class.ToType());

        // Add the XmlElementAttribute to the collection.
        attrs.get_XmlElements().Add(xElement1);

        /* Create a second XmlElementAttribute and 
           add it to the collection. */
        XmlElementAttribute xElement2 =
            new XmlElementAttribute(Train.class.ToType());
        attrs.get_XmlElements().Add(xElement2);

        /* Add the XmlAttributes to the XmlAttributeOverrides,
           specifying the member to override. */
        xOver.Add(Transportation.class.ToType(), "vehicles", attrs);

        // Create the XmlSerializer, and return it.
        XmlSerializer xSer =
            new XmlSerializer(Transportation.class.ToType(), xOver);
        return xSer;
    } //CreateOverrider

    public void SerializeObject(String fileName)
    {
        // Create an XmlSerializer instance.
        XmlSerializer xSer = CreateOverrider();

        // Create the object.
        Transportation myTransportation = new Transportation();

        /* Create two new, overriding objects that can be
           inserted into the Vehicles array. */
        myTransportation.vehicles = new ArrayList();
        Truck myTruck = new Truck();
        myTruck.name = "MyTruck";

        Train myTrain = new Train();
        myTrain.name = "MyTrain";

        myTransportation.vehicles.Add(myTruck);
        myTransportation.vehicles.Add(myTrain);

        TextWriter writer = new StreamWriter(fileName);
        xSer.Serialize(writer, myTransportation);
    } //SerializeObject
} //Test

Vererbungshierarchie

System.Object
   System.Collections.CollectionBase
    System.Xml.Serialization.XmlElementAttributes

Threadsicherheit

Alle öffentlichen statischen (Shared in Visual Basic) Member dieses Typs sind threadsicher. Bei Instanzmembern ist die Threadsicherheit nicht gewährleistet.

Plattformen

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile für Pocket PC, Windows Mobile für Smartphone, 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

.NET Compact Framework

Unterstützt in: 2.0

Siehe auch

Referenz

XmlElementAttributes-Member
System.Xml.Serialization-Namespace
XmlAttributes-Klasse

Weitere Ressourcen

Einführung in die XML-Serialisierung
Gewusst wie: Angeben eines alternativen Elementnamens für einen XML-Stream
Steuern der XML-Serialisierung mit Attributen
Beispiele für die XML-Serialisierung
XML Schema Definition-Tool (Xsd.exe)