XmlAttributes.XmlArrayItems Propriedade

Referência

Definição

Namespace:: System.Xml.Serialization

Assembly:: System.Xml.XmlSerializer.dll

Assembly:: System.Xml.dll

Assembly:: netstandard.dll

Importante

Algumas informações se referem a produtos de pré-lançamento que podem ser substancialmente modificados antes do lançamento. A Microsoft não oferece garantias, expressas ou implícitas, das informações aqui fornecidas.

Obtém ou define uma coleção de objetos que especificam como o XmlSerializer serializa os itens inseridos em uma matriz retornada por um campo público ou uma propriedade de leitura/gravação.

public:
 property System::Xml::Serialization::XmlArrayItemAttributes ^ XmlArrayItems { System::Xml::Serialization::XmlArrayItemAttributes ^ get(); };

public System.Xml.Serialization.XmlArrayItemAttributes XmlArrayItems { get; }

member this.XmlArrayItems : System.Xml.Serialization.XmlArrayItemAttributes

Public ReadOnly Property XmlArrayItems As XmlArrayItemAttributes

Valor da propriedade

XmlArrayItemAttributes

Um objeto XmlArrayItemAttributes que contém uma coleção de objetos XmlArrayItemAttribute.

Exemplos

O exemplo a seguir serializa uma classe que contém um campo chamado Members que retorna uma matriz de objetos. Dois XmlArrayItemAttribute objetos são criados para permitir que o campo aceite objetos derivados da classe base denominada Member. Cada objeto é adicionado à XmlAttributes propriedade por meio da XmlArrayItems propriedade.

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

using namespace System;
using namespace System::IO;
using namespace System::Xml;
using namespace System::Xml::Serialization;
public ref class Member
{
public:
   String^ MemberName;
};

// This is the class that will be serialized.
public ref class Group
{
public:
   array<Member^>^Members;
};

public ref class NewMember: public Member
{
public:
   int MemberID;
};

public ref class RetiredMember: public NewMember
{
public:
   DateTime RetireDate;
};

// Return an XmlSerializer used for overriding. 
XmlSerializer^ CreateOverrider()
{
   // Create XmlAttributeOverrides and XmlAttributes objects.
   XmlAttributeOverrides^ xOver = gcnew XmlAttributeOverrides;
   XmlAttributes^ xAttrs = gcnew XmlAttributes;

   // Add an override for the XmlArrayItem.    
   XmlArrayItemAttribute^ xArrayItem = gcnew XmlArrayItemAttribute( NewMember::typeid );
   xArrayItem->Namespace = "http://www.cpandl.com";
   xAttrs->XmlArrayItems->Add( xArrayItem );

   // Add a second override.
   XmlArrayItemAttribute^ xArrayItem2 = gcnew XmlArrayItemAttribute( RetiredMember::typeid );
   xArrayItem2->Namespace = "http://www.cpandl.com";
   xAttrs->XmlArrayItems->Add( xArrayItem2 );

   // Add all overrides to XmlAttribueOverrides object.
   xOver->Add( Group::typeid, "Members", xAttrs );

   // Create the XmlSerializer and return it.
   return gcnew XmlSerializer( Group::typeid,xOver );
}

void SerializeObject( String^ filename )
{
   // Create an instance of the XmlSerializer class.
   XmlSerializer^ mySerializer = CreateOverrider();

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

   // Create an instance of the class that will be serialized.
   Group^ myGroup = gcnew Group;

   // Set the object properties.
   NewMember^ m = gcnew NewMember;
   m->MemberName = "Paul";
   m->MemberID = 2;

   // Create a second member.
   RetiredMember^ m2 = gcnew RetiredMember;
   m2->MemberName = "Renaldo";
   m2->MemberID = 23;
   m2->RetireDate = DateTime(2000,10,10);
   array<Member^>^temp = {m,m2};
   myGroup->Members = temp;

   // Serialize the class, and close the TextWriter.
   mySerializer->Serialize( writer, myGroup );
   writer->Close();
}

void DeserializeObject( String^ filename )
{
   XmlSerializer^ mySerializer = CreateOverrider();
   FileStream^ fs = gcnew FileStream( filename,FileMode::Open );
   Group^ myGroup = dynamic_cast<Group^>(mySerializer->Deserialize( fs ));
   System::Collections::IEnumerator^ myEnum = myGroup->Members->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      Member^ m = safe_cast<Member^>(myEnum->Current);
      Console::WriteLine( m->MemberName );
   }
}

int main()
{
   SerializeObject( "OverrideArrayItem.xml" );
   DeserializeObject( "OverrideArrayItem.xml" );
}

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

// This is the class that will be serialized.
public class Group
{
    public Member [] Members;
}

public class Member
{
    public string MemberName;
}

public class NewMember:Member
{
    public int MemberID;
}

public class RetiredMember:NewMember
{
    public DateTime RetireDate;
}

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

   // Return an XmlSerializer used for overriding.
   public XmlSerializer CreateOverrider()
   {
      // Create XmlAttributeOverrides and XmlAttributes objects.
      XmlAttributeOverrides xOver = new XmlAttributeOverrides();
      XmlAttributes xAttrs = new XmlAttributes();

      // Add an override for the XmlArrayItem.
      XmlArrayItemAttribute xArrayItem =
      new XmlArrayItemAttribute(typeof(NewMember));
      xArrayItem.Namespace = "http://www.cpandl.com";
      xAttrs.XmlArrayItems.Add(xArrayItem);

      // Add a second override.
      XmlArrayItemAttribute xArrayItem2 =
      new XmlArrayItemAttribute(typeof(RetiredMember));
      xArrayItem2.Namespace = "http://www.cpandl.com";
      xAttrs.XmlArrayItems.Add(xArrayItem2);

      // Add all overrides to XmlAttribueOverrides object.
      xOver.Add(typeof(Group), "Members", xAttrs);

      // Create the XmlSerializer and return it.
      return new XmlSerializer(typeof(Group), xOver);
   }

   public void SerializeObject(string filename)
   {
      // Create an instance of the XmlSerializer class.
      XmlSerializer mySerializer =  CreateOverrider();
      // Writing the file requires a TextWriter.
      TextWriter writer = new StreamWriter(filename);

      // Create an instance of the class that will be serialized.
      Group myGroup = new Group();

      // Set the object properties.
      NewMember m = new NewMember();
      m.MemberName = "Paul";
      m.MemberID = 2;

      // Create a second member.
      RetiredMember m2 = new RetiredMember();
      m2.MemberName = "Renaldo";
      m2.MemberID = 23;
      m2.RetireDate = new DateTime(2000, 10,10);

      myGroup.Members = new Member[2] {m, m2};

      // Serialize the class, and close the TextWriter.
      mySerializer.Serialize(writer, myGroup);
      writer.Close();
   }

   public void DeserializeObject(string filename)
   {
      XmlSerializer mySerializer = CreateOverrider();
      FileStream fs = new FileStream(filename, FileMode.Open);
      Group myGroup = (Group)
      mySerializer.Deserialize(fs);
      foreach(Member m in myGroup.Members)
      {
          Console.WriteLine(m.MemberName);
      }
   }
}

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


' This is the class that will be serialized.
Public Class Group
    Public Members() As Member
End Class

Public Class Member
    Public MemberName As String
End Class

Public Class NewMember
    Inherits Member
    Public MemberID As Integer
End Class

Public Class RetiredMember
    Inherits NewMember
    Public RetireDate As DateTime
End Class


Public Class Run
    
    Public Shared Sub Main()
        Dim test As New Run()
        test.SerializeObject("OverrideArrayItem.xml")
        test.DeserializeObject("OverrideArrayItem.xml")
    End Sub    
    
    ' Return an XmlSerializer used for overriding. 
    Public Function CreateOverrider() As XmlSerializer
        ' Create XmlAttributeOverrides and XmlAttributes objects.
        Dim xOver As New XmlAttributeOverrides()
        Dim xAttrs As New XmlAttributes()
        
        ' Add an override for the XmlArrayItem.    
        Dim xArrayItem As New XmlArrayItemAttribute(GetType(NewMember))
        xArrayItem.Namespace = "http://www.cpandl.com"
        xAttrs.XmlArrayItems.Add(xArrayItem)
        
        ' Add a second override.
        Dim xArrayItem2 As New XmlArrayItemAttribute(GetType(RetiredMember))
        xArrayItem2.Namespace = "http://www.cpandl.com"
        xAttrs.XmlArrayItems.Add(xArrayItem2)
        
        ' Add all overrides to XmlAttribueOverrides object.
        xOver.Add(GetType(Group), "Members", xAttrs)
        
        ' Create the XmlSerializer and return it.
        Return New XmlSerializer(GetType(Group), xOver)
    End Function 
    
    
    Public Sub SerializeObject(ByVal filename As String)
        ' Create an instance of the XmlSerializer class.
        Dim mySerializer As XmlSerializer = CreateOverrider()
        ' Writing the file requires a TextWriter.
        Dim writer As New StreamWriter(filename)
        
        ' Create an instance of the class that will be serialized.
        Dim myGroup As New Group()
        
        ' Set the object properties.
        Dim m As New NewMember()
        m.MemberName = "Paul"
        m.MemberID = 2
        
        ' Create a second member.
        Dim m2 As New RetiredMember()
        m2.MemberName = "Renaldo"
        m2.MemberID = 23
        m2.RetireDate = New DateTime(2000, 10, 10)
        
        myGroup.Members = New Member(1) {m, m2}
        
        ' Serialize the class, and close the TextWriter.
        mySerializer.Serialize(writer, myGroup)
        writer.Close()
    End Sub    
    
    Public Sub DeserializeObject(ByVal filename As String)
        Dim mySerializer As XmlSerializer = CreateOverrider()
        Dim fs As New FileStream(filename, FileMode.Open)
        Dim myGroup As Group = CType(mySerializer.Deserialize(fs), Group)
        Dim m As Member
        For Each m In  myGroup.Members
            Console.WriteLine(m.MemberName)
        Next m
    End Sub
End Class

Comentários

A XmlArrayItems propriedade permite especificar os tipos derivados que podem ser inseridos em uma matriz retornada por um campo público ou uma propriedade pública de leitura/gravação. Para cada novo tipo que você deseja que o campo ou propriedade aceite, crie um XmlArrayItemAttribute objeto e Add ele para o XmlArrayItemAttributes) retornado pela XmlArrayItems propriedade. (O novo tipo deve ser derivado do tipo já aceito pelo campo ou propriedade.) Add o XmlAttributes objeto para um XmlAttributeOverrides objeto e especifique o tipo do objeto que contém o campo ou propriedade e o nome do campo ou propriedade. Construa um XmlSerializer com o objeto antes de XmlAttributeOverrides chamar Serialize ou Deserialize método.

Aplica-se a