XmlAttributes Class

Definition

Represents a collection of attribute objects that control how the XmlSerializer serializes and deserializes an object.

public class XmlAttributes
Inheritance
XmlAttributes

Examples

The following example serializes an instance of a class named Orchestra, which contains a single field named Instruments that returns an array of Instrument objects. A second class named Brass inherits from the Instrument class. The example creates an XmlAttributes object to override the Instrument field--allowing the field to accept Brass objects--and adds the XmlAttributes object to an instance of the XmlAttributeOverrides class.

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 element to the collection of elements.
      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);
      }
   }
}

Remarks

Creating the XmlAttributes is part of a process that overrides the default way the XmlSerializer serializes class instances. For example, suppose you want to serialize an object that is created from a DLL which has an inaccessible source. By using the XmlAttributeOverrides, you can augment or otherwise control how the object is serialized.

The members of the XmlAttributes class correspond directly to a family of attribute classes that control serialization. For example, the XmlText property must be set to an XmlTextAttribute, which allows you to override serialization of a field or property by instructing the XmlSerializer to serialize the property value as XML text. For a complete list of attributes that control serialization, see the XmlSerializer.

For more details on using the XmlAttributeOverrides with the XmlAttributes class, see How to: Specify an Alternate Element Name for an XML Stream.

Constructors

XmlAttributes()

Initializes a new instance of the XmlAttributes class.

XmlAttributes(ICustomAttributeProvider)

Initializes a new instance of the XmlAttributes class and customizes how the XmlSerializer serializes and deserializes an object.

Properties

XmlAnyAttribute

Gets or sets the XmlAnyAttributeAttribute to override.

XmlAnyElements

Gets the collection of XmlAnyElementAttribute objects to override.

XmlArray

Gets or sets an object that specifies how the XmlSerializer serializes a public field or read/write property that returns an array.

XmlArrayItems

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.

XmlAttribute

Gets or sets an object that specifies how the XmlSerializer serializes a public field or public read/write property as an XML attribute.

XmlChoiceIdentifier

Gets or sets an object that allows you to distinguish between a set of choices.

XmlDefaultValue

Gets or sets the default value of an XML element or attribute.

XmlElements

Gets a collection of objects that specify how the XmlSerializer serializes a public field or read/write property as an XML element.

XmlEnum

Gets or sets an object that specifies how the XmlSerializer serializes an enumeration member.

XmlIgnore

Gets or sets a value that specifies whether or not the XmlSerializer serializes a public field or public read/write property.

Xmlns

Gets or sets a value that specifies whether to keep all namespace declarations when an object containing a member that returns an XmlSerializerNamespaces object is overridden.

XmlRoot

Gets or sets an object that specifies how the XmlSerializer serializes a class as an XML root element.

XmlText

Gets or sets an object that instructs the XmlSerializer to serialize a public field or public read/write property as XML text.

XmlType

Gets or sets an object that specifies how the XmlSerializer serializes a class to which the XmlTypeAttribute has been applied.

Methods

Equals(Object)

Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetHashCode()

Serves as the default hash function.

(Inherited from Object)
GetType()

Gets the Type of the current instance.

(Inherited from Object)
MemberwiseClone()

Creates a shallow copy of the current Object.

(Inherited from Object)
ToString()

Returns a string that represents the current object.

(Inherited from Object)

Applies to

Product Versions
.NET Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard 2.0, 2.1
UWP 10.0

See also