XmlAttributes.XmlArrayItems Property

Definition

Namespace:

System.Xml.Serialization

Assembly:

System.Xml.XmlSerializer.dll

Source:

XmlAttributes.cs

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.

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

Property Value

XmlArrayItemAttributes

An XmlArrayItemAttributes object that contains a collection of XmlArrayItemAttribute objects.

Examples

The following example serializes a class that contains a field named Members that returns an array of objects. Two XmlArrayItemAttribute objects are created to allow the field to accept objects that derive from the base class named Member. Each object is added to the XmlAttributes through the XmlArrayItems property.

#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

Remarks

The XmlArrayItems property allows you to specify the derived types that can be inserted into an array returned by a public field or public read/write property. For each new type you want the field or property to accept, create an XmlArrayItemAttribute object and Add it to the XmlArrayItemAttributes) returned by the XmlArrayItems property. (The new type must be derived from the type already accepted by the field or property.) Add the XmlAttributes object to an XmlAttributeOverrides object and specify the type of the object that contains the field or property, and the name of the field or property. Construct an XmlSerializer with the XmlAttributeOverrides object before calling Serialize or Deserialize method.