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XmlElementAttributes Class

Represents a collection of XmlElementAttribute objects used by the XmlSerializer to override the default way it serializes a class.

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

public class XmlElementAttributes : CollectionBase

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.

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 specifies the types of objects the XmlSerializer inserts 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.

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);
   }
}
#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");
}

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

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

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

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