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XmlElementAttributes Class

Represents a collection of XmlElementAttribute, which the XmlSerializer uses to override the default way it serializes a class.

For a list of all members of this type, see XmlElementAttributes Members.

System.Object
   System.Collections.CollectionBase
      System.Xml.Serialization.XmlElementAttributes

[Visual Basic]
Public Class XmlElementAttributes
   Inherits CollectionBase
[C#]
public class XmlElementAttributes : CollectionBase
[C++]
public __gc class XmlElementAttributes : public CollectionBase
[JScript]
public class XmlElementAttributes extends CollectionBase

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Remarks

The XmlElementAttributes is returned by the XmlElements property of the XmlAttributes class. By using the XmlAttributeOverrides class and the XmlAttributes class, you can override the default way that the XmlSerializer serializes a class.

Example

[Visual Basic, C#, C++] The following example serializes the Transportation class, which contains a single field named Vehicles that returns an ArrayList. The example first applies two instances of the XmlElementAttribute class to the Vehicles field that specify the types of objects the XmlSerializer can insert into the array. The example then creates two XmlElementAttribute objects to override the behavior of the attributes applied to the Vehicles property. The two overriding objects are added to the XmlElementAttributes collection of an XmlAttributes. Lastly, the example adds the XmlAttributes to an XmlAttributeOverrides, allowing the XmlSerializer to insert the new object types into the ArrayList returned by the Vehicles field.

[Visual Basic] 
Imports System
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


[C#] 
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);
   }
}


[C++] 
#using <mscorlib.dll>
#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 __gc class Car
{
public:
   String* Name;
};

public __gc class Plane
{
public:
   String* Name;
};

public __gc class Truck
{
public:
   String* Name;
};

public __gc class Train
{
public:
   String* Name;
};

public __gc class Transportation
{
   // Override these two XmlElementAttributes.
public:
   [XmlElement(__typeof(Car)),
      XmlElement(__typeof(Plane))]
   ArrayList* Vehicles;
};

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), S"Vehicles", attrs);

   // Create the XmlSerializer, and return it.
   XmlSerializer* xSer = new XmlSerializer
      (__typeof(Transportation), xOver);
   return xSer;
}

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 = S"MyTruck";

   Train* myTrain = new Train();
   myTrain->Name = S"MyTrain";

   myTransportation->Vehicles->Add(myTruck);
   myTransportation->Vehicles->Add(myTrain);

   TextWriter* writer = new StreamWriter(filename);
   xSer->Serialize(writer, myTransportation);
}

int main()
{
   SerializeObject(S"OverrideElement.xml");
}

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Namespace: System.Xml.Serialization

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

Assembly: System.Xml (in System.Xml.dll)

See Also

XmlElementAttributes Members | System.Xml.Serialization Namespace

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