XmlAttributes Classe

Définition

Représente une collection d'objets attributs qui contrôlent la manière dont XmlSerializer sérialise et désérialise un objet.Represents a collection of attribute objects that control how the XmlSerializer serializes and deserializes an object.

public ref class XmlAttributes
public class XmlAttributes
type XmlAttributes = class
Public Class XmlAttributes
Héritage
XmlAttributes

Exemples

L’exemple suivant sérialise une instance d’une classe nommée Orchestra, qui contient un champ unique nommé Instruments qui retourne un tableau d’objets Instrument.The following example serializes an instance of a class named Orchestra, which contains a single field named Instruments that returns an array of Instrument objects. Une deuxième classe nommée Brass hérite de la classe Instrument.A second class named Brass inherits from the Instrument class. L’exemple crée un objet XmlAttributes pour remplacer le champ Instrument, en autorisant le champ à accepter Brass objets, et ajoute l’objet XmlAttributes à une instance de la classe XmlAttributeOverrides.The example creates an XmlAttributes object to override the Instrument field--allowing the field to accept Brass objects--and adds the XmlAttributes object to an instance of the XmlAttributeOverrides class.

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

using namespace System;
using namespace System::IO;
using namespace System::Xml::Serialization;
public ref class Instrument
{
public:
   String^ Name;
};

public ref class Brass: public Instrument
{
public:
   bool IsValved;
};

public ref class Orchestra
{
public:
   array<Instrument^>^Instruments;
};

void SerializeObject( String^ filename )
{
   /* Each overridden field, property, or type requires 
      an XmlAttributes object. */
   XmlAttributes^ attrs = gcnew XmlAttributes;

   /* Create an XmlElementAttribute to override the 
      field that returns Instrument objects. The overridden field
      returns Brass objects instead. */
   XmlElementAttribute^ attr = gcnew XmlElementAttribute;
   attr->ElementName = "Brass";
   attr->Type = Brass::typeid;

   // Add the element to the collection of elements.
   attrs->XmlElements->Add( attr );

   // Create the XmlAttributeOverrides object.
   XmlAttributeOverrides^ attrOverrides = gcnew XmlAttributeOverrides;

   /* Add the type of the class that contains the overridden 
      member and the XmlAttributes to override it with to the 
      XmlAttributeOverrides object. */
   attrOverrides->Add( Orchestra::typeid, "Instruments", attrs );

   // Create the XmlSerializer using the XmlAttributeOverrides.
   XmlSerializer^ s = gcnew XmlSerializer( Orchestra::typeid,attrOverrides );

   // Writing the file requires a TextWriter.
   TextWriter^ writer = gcnew StreamWriter( filename );

   // Create the object that will be serialized.
   Orchestra^ band = gcnew Orchestra;

   // Create an object of the derived type.
   Brass^ i = gcnew Brass;
   i->Name = "Trumpet";
   i->IsValved = true;
   array<Instrument^>^myInstruments = {i};
   band->Instruments = myInstruments;

   // Serialize the object.
   s->Serialize( writer, band );
   writer->Close();
}

void DeserializeObject( String^ filename )
{
   XmlAttributeOverrides^ attrOverrides = gcnew XmlAttributeOverrides;
   XmlAttributes^ attrs = gcnew XmlAttributes;

   // Create an XmlElementAttribute to override the Instrument.
   XmlElementAttribute^ attr = gcnew XmlElementAttribute;
   attr->ElementName = "Brass";
   attr->Type = Brass::typeid;

   // Add the element to the collection of elements.
   attrs->XmlElements->Add( attr );
   attrOverrides->Add( Orchestra::typeid, "Instruments", attrs );

   // Create the XmlSerializer using the XmlAttributeOverrides.
   XmlSerializer^ s = gcnew XmlSerializer( Orchestra::typeid,attrOverrides );
   FileStream^ fs = gcnew FileStream( filename,FileMode::Open );
   Orchestra^ band = dynamic_cast<Orchestra^>(s->Deserialize( fs ));
   Console::WriteLine( "Brass:" );

   /* The difference between deserializing the overridden 
      XML document and serializing it is this: To read the derived 
      object values, you must declare an object of the derived type 
      (Brass), and cast the Instrument instance to it. */
   Brass^ b;
   System::Collections::IEnumerator^ myEnum = band->Instruments->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      Instrument^ i = safe_cast<Instrument^>(myEnum->Current);
      b = dynamic_cast<Brass^>(i);
      Console::WriteLine( "{0}\n{1}", b->Name, b->IsValved );
   }
}

int main()
{
   SerializeObject( "Override.xml" );
   DeserializeObject( "Override.xml" );
}
using System;
using System.IO;
using System.Xml.Serialization;

public class Orchestra
{
   public Instrument[] Instruments;
}   

public class Instrument
{
   public string Name;
}

public class Brass:Instrument
{
   public bool IsValved;
}

public class Run
{
    public static void Main()
    {
       Run test = new Run();
       test.SerializeObject("Override.xml");
       test.DeserializeObject("Override.xml");
    }

    public void SerializeObject(string filename)
    {
      /* Each overridden field, property, or type requires 
      an XmlAttributes object. */
      XmlAttributes attrs = new XmlAttributes();

      /* Create an XmlElementAttribute to override the 
      field that returns Instrument objects. The overridden field
      returns Brass objects instead. */
      XmlElementAttribute attr = new XmlElementAttribute();
      attr.ElementName = "Brass";
      attr.Type = typeof(Brass);

      // Add the element to the collection of elements.
      attrs.XmlElements.Add(attr);

      // Create the XmlAttributeOverrides object.
      XmlAttributeOverrides attrOverrides = new XmlAttributeOverrides();

      /* Add the type of the class that contains the overridden 
      member and the XmlAttributes to override it with to the 
      XmlAttributeOverrides object. */
      attrOverrides.Add(typeof(Orchestra), "Instruments", attrs);

      // Create the XmlSerializer using the XmlAttributeOverrides.
      XmlSerializer s = 
      new XmlSerializer(typeof(Orchestra), attrOverrides);

      // Writing the file requires a TextWriter.
      TextWriter writer = new StreamWriter(filename);

      // Create the object that will be serialized.
      Orchestra band = new Orchestra();
      
      // Create an object of the derived type.
      Brass i = new Brass();
      i.Name = "Trumpet";
      i.IsValved = true;
      Instrument[] myInstruments = {i};
      band.Instruments = myInstruments;

      // Serialize the object.
      s.Serialize(writer,band);
      writer.Close();
   }

   public void DeserializeObject(string filename)
   {
      XmlAttributeOverrides attrOverrides = 
         new XmlAttributeOverrides();
      XmlAttributes attrs = new XmlAttributes();

      // Create an XmlElementAttribute to override the Instrument.
      XmlElementAttribute attr = new XmlElementAttribute();
      attr.ElementName = "Brass";
      attr.Type = typeof(Brass);

      // Add the element to the collection of elements.
      attrs.XmlElements.Add(attr);

      attrOverrides.Add(typeof(Orchestra), "Instruments", attrs);

      // Create the XmlSerializer using the XmlAttributeOverrides.
      XmlSerializer s = 
      new XmlSerializer(typeof(Orchestra), attrOverrides);

      FileStream fs = new FileStream(filename, FileMode.Open);
      Orchestra band = (Orchestra) s.Deserialize(fs);
      Console.WriteLine("Brass:");

      /* The difference between deserializing the overridden 
      XML document and serializing it is this: To read the derived 
      object values, you must declare an object of the derived type 
      (Brass), and cast the Instrument instance to it. */
      Brass b;
      foreach(Instrument i in band.Instruments) 
      {
         b = (Brass)i;
         Console.WriteLine(
         b.Name + "\n" + 
         b.IsValved);
      }
   }
}

Imports System.IO
Imports System.Xml.Serialization

Public Class Orchestra
    Public Instruments() As Instrument
End Class

Public Class Instrument
    Public Name As String
End Class

Public Class Brass
    Inherits Instrument
    Public IsValved As Boolean
End Class


Public Class Run
    
    Public Shared Sub Main()
        Dim test As New Run()
        test.SerializeObject("Override.xml")
        test.DeserializeObject("Override.xml")
    End Sub    
    
    Public Sub SerializeObject(ByVal filename As String)
        ' Each overridden field, property, or type requires
        ' an XmlAttributes object. 
        Dim attrs As New XmlAttributes()
        
        ' Create an XmlElementAttribute to override the
        ' field that returns Instrument objects. The overridden field
        ' returns Brass objects instead. 
        Dim attr As New XmlElementAttribute()
        attr.ElementName = "Brass"
        attr.Type = GetType(Brass)
        
        ' Add the element to the collection of elements.
        attrs.XmlElements.Add(attr)
        
        ' Create the XmlAttributeOverrides object.
        Dim attrOverrides As New XmlAttributeOverrides()
        
        ' Add the type of the class that contains the overridden
        ' member and the XmlAttributes to override it with to the
        ' XmlAttributeOverrides object. 
        attrOverrides.Add(GetType(Orchestra), "Instruments", attrs)
        
        ' Create the XmlSerializer using the XmlAttributeOverrides.
        Dim s As New XmlSerializer(GetType(Orchestra), attrOverrides)
        
        ' Writing the file requires a TextWriter.
        Dim writer As New StreamWriter(filename)
        
        ' Create the object that will be serialized.
        Dim band As New Orchestra()
        
        ' Create an object of the derived type.
        Dim i As New Brass()
        i.Name = "Trumpet"
        i.IsValved = True
        Dim myInstruments() As Instrument = {i}
        band.Instruments = myInstruments
        
        ' Serialize the object.
        s.Serialize(writer, band)
        writer.Close()
    End Sub
    
    
    Public Sub DeserializeObject(ByVal filename As String)
        Dim attrOverrides As New XmlAttributeOverrides()
        Dim attrs As New XmlAttributes()
        
        ' Create an XmlElementAttribute to override the Instrument.
        Dim attr As New XmlElementAttribute()
        attr.ElementName = "Brass"
        attr.Type = GetType(Brass)
        
        ' Add the element to the collection of elements.
        attrs.XmlElements.Add(attr)
        
        attrOverrides.Add(GetType(Orchestra), "Instruments", attrs)
        
        ' Create the XmlSerializer using the XmlAttributeOverrides.
        Dim s As New XmlSerializer(GetType(Orchestra), attrOverrides)
        
        Dim fs As New FileStream(filename, FileMode.Open)
        Dim band As Orchestra = CType(s.Deserialize(fs), Orchestra)
        Console.WriteLine("Brass:")
        
        ' The difference between deserializing the overridden
        ' XML document and serializing it is this: To read the derived
        ' object values, you must declare an object of the derived type
        ' (Brass), and cast the Instrument instance to it. 
        Dim b As Brass
        Dim i As Instrument
        For Each i In  band.Instruments
            b = CType(i, Brass)
            Console.WriteLine(b.Name + ControlChars.Cr + _
                              b.IsValved.ToString())
        Next i
    End Sub
End Class

Remarques

La création de l' XmlAttributes fait partie d’un processus qui remplace la méthode par défaut de sérialisation des instances de classe par le XmlSerializer.Creating the XmlAttributes is part of a process that overrides the default way the XmlSerializer serializes class instances. Supposons, par exemple, que vous vouliez sérialiser un objet créé à partir d’une DLL qui a une source inaccessible.For example, suppose you want to serialize an object that is created from a DLL which has an inaccessible source. À l’aide de l' XmlAttributeOverrides, vous pouvez augmenter ou contrôler la façon dont l’objet est sérialisé.By using the XmlAttributeOverrides, you can augment or otherwise control how the object is serialized.

Les membres de la classe XmlAttributes correspondent directement à une famille de classes d’attributs qui contrôlent la sérialisation.The members of the XmlAttributes class correspond directly to a family of attribute classes that control serialization. Par exemple, la propriété XmlText doit être définie sur un XmlTextAttribute, ce qui vous permet de substituer la sérialisation d’un champ ou d’une propriété en demandant à l' XmlSerializer de sérialiser la valeur de la propriété en tant que texte XML.For example, the XmlText property must be set to an XmlTextAttribute, which allows you to override serialization of a field or property by instructing the XmlSerializer to serialize the property value as XML text. Pour obtenir la liste complète des attributs qui contrôlent la sérialisation, consultez la XmlSerializer.For a complete list of attributes that control serialization, see the XmlSerializer.

Pour plus d’informations sur l’utilisation de la XmlAttributeOverrides avec la classe XmlAttributes, consultez Comment : spécifier un nom d’élément différent pour un flux XML.For more details on using the XmlAttributeOverrides with the XmlAttributes class, see How to: Specify an Alternate Element Name for an XML Stream.

Constructeurs

XmlAttributes()

Initialise une nouvelle instance de la classe XmlAttributes.Initializes a new instance of the XmlAttributes class.

XmlAttributes(ICustomAttributeProvider)

Initialise une nouvelle instance de la classe XmlAttributes et personnalise la manière dont le XmlSerializer sérialise et désérialise un objet.Initializes a new instance of the XmlAttributes class and customizes how the XmlSerializer serializes and deserializes an object.

Propriétés

XmlAnyAttribute

Obtient ou définit le XmlAnyAttributeAttribute à substituer.Gets or sets the XmlAnyAttributeAttribute to override.

XmlAnyElements

Obtient la collection d'objets XmlAnyElementAttribute à substituer.Gets the collection of XmlAnyElementAttribute objects to override.

XmlArray

Obtient ou définit un objet qui spécifie la façon dont XmlSerializer sérialise un champ public ou une propriété en lecture/écriture publique retournant un tableau.Gets or sets an object that specifies how the XmlSerializer serializes a public field or read/write property that returns an array.

XmlArrayItems

Obtient ou définit une collection d'objets qui spécifient comment XmlSerializer sérialise les éléments qui sont insérés dans un tableau retourné par un champ public ou une propriété en lecture/écriture publique.Gets or sets a collection of objects that specify how the XmlSerializer serializes items inserted into an array returned by a public field or read/write property.

XmlAttribute

Obtient ou définit un objet qui spécifie la façon dont XmlSerializer sérialise un champ public ou une propriété en lecture/écriture publique comme un attribut XML.Gets or sets an object that specifies how the XmlSerializer serializes a public field or public read/write property as an XML attribute.

XmlChoiceIdentifier

Obtient ou définit un objet qui vous permet de faire la différence entre plusieurs options.Gets or sets an object that allows you to distinguish between a set of choices.

XmlDefaultValue

Obtient ou définit la valeur par défaut d'un élément XML ou d'un attribut XML.Gets or sets the default value of an XML element or attribute.

XmlElements

Obtient une collection d'objets qui spécifient comment XmlSerializer sérialise un champ public ou une propriété en lecture/écriture publique en tant qu'élément XML.Gets a collection of objects that specify how the XmlSerializer serializes a public field or read/write property as an XML element.

XmlEnum

Obtient ou définit un objet qui spécifie la façon dont XmlSerializer sérialise un membre de l'énumération.Gets or sets an object that specifies how the XmlSerializer serializes an enumeration member.

XmlIgnore

Obtient ou définit une valeur qui spécifie si XmlSerializer sérialise ou non un champ public ou une propriété en lecture/écriture publique.Gets or sets a value that specifies whether or not the XmlSerializer serializes a public field or public read/write property.

Xmlns

Obtient ou définit une valeur spécifiant si toutes les déclarations d'espace de noms doivent être conservées lors de substitution d'un objet qui contient un membre retournant un objet XmlSerializerNamespaces.Gets or sets a value that specifies whether to keep all namespace declarations when an object containing a member that returns an XmlSerializerNamespaces object is overridden.

XmlRoot

Obtient ou définit un objet qui spécifie la façon dont XmlSerializer sérialise une classe comme élément racine XML.Gets or sets an object that specifies how the XmlSerializer serializes a class as an XML root element.

XmlText

Obtient ou définit un objet qui commande à XmlSerializer de sérialiser un champ public ou une propriété en lecture/écriture publique comme texte XML.Gets or sets an object that instructs the XmlSerializer to serialize a public field or public read/write property as XML text.

XmlType

Obtient ou définit un objet qui spécifie la façon dont XmlSerializer sérialise une classe à laquelle XmlTypeAttribute a été appliqué.Gets or sets an object that specifies how the XmlSerializer serializes a class to which the XmlTypeAttribute has been applied.

Méthodes

Equals(Object)

Détermine si l'objet spécifié est égal à l'objet actuel.Determines whether the specified object is equal to the current object.

(Hérité de Object)
GetHashCode()

Sert de fonction de hachage par défaut.Serves as the default hash function.

(Hérité de Object)
GetType()

Obtient le Type de l'instance actuelle.Gets the Type of the current instance.

(Hérité de Object)
MemberwiseClone()

Crée une copie superficielle du Object actuel.Creates a shallow copy of the current Object.

(Hérité de Object)
ToString()

Retourne une chaîne qui représente l'objet en cours.Returns a string that represents the current object.

(Hérité de Object)

S’applique à

Voir aussi