XmlAttributeOverrides クラス

定義

オブジェクトをシリアル化または逆シリアル化するために XmlSerializer を使用するときに、プロパティ、フィールド、クラスの各属性をユーザーがオーバーライドできるようにします。Allows you to override property, field, and class attributes when you use the XmlSerializer to serialize or deserialize an object.

public ref class XmlAttributeOverrides
public class XmlAttributeOverrides
type XmlAttributeOverrides = class
Public Class XmlAttributeOverrides
継承
XmlAttributeOverrides

次の例では、とOrchestraいう名前のクラスをシリアル化Instrumentsします。このクラスInstrumentには、オブジェクトの配列を返すという1つのフィールドが含まれています。The following example serializes a class named Orchestra, which contains a single field named Instruments that returns an array of Instrument objects. という名前Brassの2番目Instrumentのクラスは、クラスから継承します。A second class named Brass inherits from the Instrument class. この例では、 XmlAttributeOverridesクラスのインスタンスを使用してInstrumentフィールドをオーバーライドし、フィールドBrassがオブジェクトを受け取ることができるようにします。The example uses an instance of the XmlAttributeOverrides class to override the Instrument field, allowing the field to accept Brass objects.

#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 XmlElementAttribute to the collection of objects.
   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 XmlElementAttribute to the collection of objects.
      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);
      }
   }
}

Option Explicit
Option Strict

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(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 XmlElementAttribute to the collection of objects.
        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)
        Next i
    End Sub
End Class

注釈

を使用するXmlSerializerと、オブジェクトのセットをシリアル化する既定の方法をでオーバーライドできます。 XmlAttributeOverridesThe XmlAttributeOverrides enables the XmlSerializer to override the default way of serializing a set of objects. この方法でシリアル化をオーバーライドすると、2つの用途があります。最初に、ソースにアクセスできない場合でも、DLL 内で見つかったオブジェクトのシリアル化を制御および拡張できます。次に、シリアル化可能なクラスの1つのセットを作成できますが、複数の方法でオブジェクトをシリアル化できます。Overriding serialization in this way has two uses: first, you can control and augment the serialization of objects found in a DLL--even if you do not have access to the source; second, you can create one set of serializable classes, but serialize the objects in multiple ways. たとえば、クラスインスタンスのメンバーを XML 要素としてシリアル化する代わりに、それらを XML 属性としてシリアル化することで、より効率的に転送できるドキュメントにすることができます。For example, instead of serializing members of a class instance as XML elements, you can serialize them as XML attributes, resulting in a more efficient document to transport.

XmlAttributeOverridesオブジェクトを作成したら、それを引数としてXmlSerializerコンストラクターに渡します。After you create an XmlAttributeOverrides object, you pass it as an argument to the XmlSerializer constructor. 結果XmlSerializerのは、 XmlAttributeOverridesに含まれるデータを使用して、オブジェクトをシリアル化する方法を制御する属性をオーバーライドします。The resulting XmlSerializer uses the data contained by the XmlAttributeOverrides to override attributes that control how objects are serialized. これを実現するためXmlAttributeOverridesに、には、オーバーライドされるオブジェクト型のコレクションと、オーバーライドXmlAttributesされた各オブジェクト型に関連付けられたオブジェクトが含まれています。To accomplish this, the XmlAttributeOverrides contains a collection of the object types that are overridden, as well as an XmlAttributes object associated with each overridden object type. オブジェクトXmlAttributes自体には、各フィールド、プロパティ、またはクラスをシリアル化する方法を制御する属性オブジェクトの適切なセットが含まれています。The XmlAttributes object itself contains an appropriate set of attribute objects that control how each field, property, or class is serialized.

XmlAttributeOverridesオブジェクトを作成して使用するプロセスは次のとおりです。The process for creating and using an XmlAttributeOverrides object is as follows:

  1. オブジェクトをXmlAttributes作成します。Create an XmlAttributes object.

  2. オーバーライドされるオブジェクトに適した属性オブジェクトを作成します。Create an attribute object that is appropriate to the object being overridden. たとえば、フィールドまたはプロパティをオーバーライドするには、 XmlElementAttribute新しい派生型を使用してを作成します。For example, to override a field or property, create an XmlElementAttribute, using the new, derived type. 必要に応じて、新しいElementName、またNamespaceは基本クラスの属性名または名前空間をオーバーライドするを割り当てることができます。You can optionally assign a new ElementName, or Namespace that overrides the base class's attribute name or namespace.

  3. 属性オブジェクトを適切なXmlAttributesプロパティまたはコレクションに追加します。Add the attribute object to the appropriate XmlAttributes property or collection. たとえば、をXmlElementAttribute XmlAttributesオブジェクトのXmlElementsコレクションに追加して、オーバーライドされるメンバーの名前を指定します。For example, you would add the XmlElementAttribute to the XmlElements collection of the XmlAttributes object, specifying the member name that is being overridden.

  4. オブジェクトをXmlAttributeOverrides作成します。Create an XmlAttributeOverrides object.

  5. メソッドを使用して、 XmlAttributesオブジェクトをXmlAttributeOverridesオブジェクトに追加します。 AddUsing the Add method, add the XmlAttributes object to the XmlAttributeOverrides object. オーバーライドするオブジェクトがXmlRootAttributeまたはXmlTypeAttributeの場合は、オーバーライドされたオブジェクトの型を指定するだけです。If the object being overridden is an XmlRootAttribute or XmlTypeAttribute, you need only to specify the type of the overridden object. ただし、フィールドまたはプロパティをオーバーライドする場合は、オーバーライドされたメンバーの名前も指定する必要があります。But if you are overriding a field or property, you must also specify the name of the overridden member.

  6. を構築XmlSerializerするときに、 XmlAttributeOverridesXmlSerializerコンストラクターに渡します。When constructing the XmlSerializer, pass the XmlAttributeOverrides to the XmlSerializer constructor.

  7. 生成XmlSerializerされたを使用して、派生クラスオブジェクトをシリアル化または逆シリアル化します。Use the resulting XmlSerializer to serialize or deserialize the derived class objects.

コンストラクター

XmlAttributeOverrides()

XmlAttributeOverrides クラスの新しいインスタンスを初期化します。Initializes a new instance of the XmlAttributeOverrides class.

プロパティ

Item[Type, String]

指定された (基本クラス) 型に関連付けられたオブジェクトを取得します。Gets the object associated with the specified (base-class) type. メンバー パラメーターは、オーバーライドされた基本クラス メンバーを指定します。The member parameter specifies the base-class member that is overridden.

Item[Type]

指定された (基本クラス) 型に関連付けられたオブジェクトを取得します。Gets the object associated with the specified, base-class, type.

メソッド

Add(Type, String, XmlAttributes)

XmlAttributes オブジェクトを XmlAttributes オブジェクトのコレクションに追加します。Adds an XmlAttributes object to the collection of XmlAttributes objects. type パラメーターは、オーバーライドされるオブジェクトを指定します。The type parameter specifies an object to be overridden. member パラメーターは、オーバーライドされるメンバーの名前を指定します。The member parameter specifies the name of a member that is overridden.

Add(Type, XmlAttributes)

XmlAttributes オブジェクトを XmlAttributes オブジェクトのコレクションに追加します。Adds an XmlAttributes object to the collection of XmlAttributes objects. type パラメーターは、XmlAttributes オブジェクトによってオーバーライドされるオブジェクトを指定します。The type parameter specifies an object to be overridden by the XmlAttributes object.

Equals(Object)

指定したオブジェクトが、現在のオブジェクトと等しいかどうかを判断します。Determines whether the specified object is equal to the current object.

(継承元 Object)
GetHashCode()

既定のハッシュ関数として機能します。Serves as the default hash function.

(継承元 Object)
GetType()

現在のインスタンスの Type を取得します。Gets the Type of the current instance.

(継承元 Object)
MemberwiseClone()

現在の Object の簡易コピーを作成します。Creates a shallow copy of the current Object.

(継承元 Object)
ToString()

現在のオブジェクトを表す文字列を返します。Returns a string that represents the current object.

(継承元 Object)

適用対象

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