XmlElementAttributes Classe

Definizione

public ref class XmlElementAttributes : System::Collections::IList

public ref class XmlElementAttributes : System::Collections::CollectionBase

public class XmlElementAttributes : System.Collections.IList

public class XmlElementAttributes : System.Collections.CollectionBase

type XmlElementAttributes = class
    interface ICollection
    interface IEnumerable
    interface IList

type XmlElementAttributes = class
    inherit CollectionBase

Public Class XmlElementAttributes
Implements IList

Public Class XmlElementAttributes
Inherits CollectionBase

Ereditarietà

Object

XmlElementAttributes

Ereditarietà

Object

CollectionBase

XmlElementAttributes

Implementazioni

ICollection IEnumerable IList

Esempio

L'esempio seguente serializza la Transportation classe , che contiene un singolo campo denominato Vehicles che restituisce un oggetto ArrayList. Nell'esempio vengono prima applicati due istanze della XmlElementAttribute classe al Vehicles campo che specifica i tipi di oggetti inseriti XmlSerializer nella matrice. Nell'esempio vengono quindi creati due XmlElementAttribute oggetti per eseguire l'override del comportamento degli attributi applicati alla Vehicles proprietà . I due oggetti di override vengono aggiunti all'insieme XmlElementAttributes di un oggetto XmlAttributes. Infine, l'esempio aggiunge a XmlAttributes un XmlAttributeOverridesoggetto , consentendo XmlSerializer a di inserire i nuovi tipi di oggetto nell'oggetto ArrayList restituito dal Vehicles campo .

#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" );
}

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);
   }
}

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

Commenti

L'oggetto XmlElementAttributes XmlElements viene restituito dalla proprietà della XmlAttributes classe . Usando la XmlAttributeOverrides classe e la XmlAttributes classe , è possibile eseguire l'override del modo predefinito in cui serializza XmlSerializer una classe.

Costruttori

Proprietà

Metodi

Implementazioni dell'interfaccia esplicita

Metodi di estensione

Si applica a

Vedi anche

• XmlAttributes
• Introduzione alla serializzazione XML
• Procedura: specificare un nome di elemento alternativo per un flusso XML
• Controllo della serializzazione XML mediante attributi
• Esempi di serializzazione XML
• XML Schema Definition Tool (Xsd.exe)