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XmlAttributeAttribute Class

Specifies that the XmlSerializer should serialize the class member as an XML attribute.

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

System.Object
   System.Attribute
      System.Xml.Serialization.XmlAttributeAttribute

[Visual Basic]
<AttributeUsage(AttributeTargets.Property Or AttributeTargets.Field _
   Or AttributeTargets.Parameter Or AttributeTargets.ReturnValue)>
Public Class XmlAttributeAttribute
   Inherits Attribute
[C#]
[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field
   | AttributeTargets.Parameter | AttributeTargets.ReturnValue)]
public class XmlAttributeAttribute : Attribute
[C++]
[AttributeUsage(AttributeTargets::Property |
   AttributeTargets::Field | AttributeTargets::Parameter |
   AttributeTargets::ReturnValue)]
public __gc class XmlAttributeAttribute : public Attribute
[JScript]
public
   AttributeUsage(AttributeTargets.Property | AttributeTargets.Field |
   AttributeTargets.Parameter | AttributeTargets.ReturnValue)
class XmlAttributeAttribute extends Attribute

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 XmlAttributeAttribute belongs to a family of attributes that controls how the XmlSerializer serializes, or deserializes, an object. For a complete list of similar attributes, see Attributes That Control XML Serialization.

When applied to a public field or property, the XmlAttributeAttribute informs the XmlSerializer to serialize the member as an XML attribute. By default, the XmlSerializer serializes public fields and properties as XML elements.

You can assign the XmlAttributeAttribute only to public fields or public properties that return a value (or array of values) that can be mapped to one of the XML Schema definition language (XSD) simple types (including all built-in datatypes derived from the XSD anySimpleType type). The possible types include any that can be mapped to the XSD simple types, including Guid, Char, and enumerations. See the DataType property for a list of XSD types and how they are mapped to .NET data types.

There are two special attributes that can be set with the XmlAttributeAttribute: the xml:lang (specifies language) and xml:space (specifies how to handle white space) attributes. These attributes are intended to convey information that is relevant only to an application processing the XML. Examples of setting these are shown in the following code.

[C#] 
[XmlAttribute("xml:lang")]
public string Lang;
// Set this to 'default' or 'preserve'.
[XmlAttribute("space", 
Namespace = "http://www.w3.org/XML/1998/namespace")]
public string Space 
[Visual Basic]
<XmlAttribute("xml:lang")> _
Public Lang As String 
' Set this to 'default' or 'preserve'.
<XmlAttribute("space", _
Namespace:= "http://www.w3.org/XML/1998/namespace")> _
Public Space As String

For more information about using attributes, see Extending Metadata Using Attributes.

Note   In your code, you can use the word XmlAttribute instead of the longer XmlAttributeAttribute.

Example

[Visual Basic, C#, C++] The following example serializes a class that contains several fields to which the XmlAttributeAttribute is applied.

[Visual Basic] 
Option Explicit
Option Strict

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


Public Class Group
    <XmlAttribute(Namespace := "http://www.cpandl.com")> _
        Public GroupName As String    
    <XmlAttribute(DataType := "base64Binary")> _
        Public GroupNumber() As Byte    
    <XmlAttribute(DataType := "date", AttributeName := "CreationDate")> _
        Public Today As DateTime
End Class

Public Class Run
    
    Public Shared Sub Main()
        Dim test As New Run()
        test.SerializeObject("Attributes.xml")
    End Sub 
    
    Public Sub SerializeObject(ByVal filename As String)
        ' Create an instance of the XmlSerializer class.
        Dim mySerializer As New XmlSerializer(GetType(Group))
        
        ' 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.
        myGroup.GroupName = ".NET"
        
        Dim hexByte() As Byte = {Convert.ToByte(100), Convert.ToByte(50)}
        myGroup.GroupNumber = hexByte
        
        Dim myDate As New DateTime(2001, 1, 10)
        myGroup.Today = myDate
        
        ' Serialize the class, and close the TextWriter.
        mySerializer.Serialize(writer, myGroup)
        writer.Close()
    End Sub
End Class


[C#] 
using System;
using System.IO;
using System.Xml;
using System.Xml.Serialization;
using System.Xml.Schema;

public class Group
{
   [XmlAttribute (Namespace = "http://www.cpandl.com")]
   public string GroupName;
   
   [XmlAttribute(DataType = "base64Binary")]
   public Byte [] GroupNumber;

   [XmlAttribute(DataType = "date", AttributeName = "CreationDate")]
   public DateTime Today;
}


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


   public void SerializeObject(string filename)
   {
      // Create an instance of the XmlSerializer class.
      XmlSerializer mySerializer =  
      new XmlSerializer(typeof(Group));

      // 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.
      myGroup.GroupName = ".NET";

      Byte [] hexByte = new Byte[2]{Convert.ToByte(100),
      Convert.ToByte(50)};
      myGroup.GroupNumber = hexByte;

      DateTime myDate = new DateTime(2001,1,10);
      myGroup.Today = myDate;

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

[C++] 
#using <mscorlib.dll>
#using <System.Xml.dll>
using namespace System;
using namespace System::IO;
using namespace System::Xml;
using namespace System::Xml::Serialization;
using namespace System::Xml::Schema;

public __gc class Group
{
public:
   [XmlAttributeAttribute (Namespace = S"http://www.cpandl.com")]
   String* GroupName;

   [XmlAttributeAttribute(DataType = S"base64Binary")]
   Byte GroupNumber[];

   [XmlAttributeAttribute(DataType = S"date", AttributeName = S"CreationDate")]
   DateTime Today;
};

void SerializeObject(String* filename)
{
   // Create an instance of the XmlSerializer class.
   XmlSerializer* mySerializer =  
      new XmlSerializer(__typeof(Group));

   // 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.
   myGroup->GroupName = S".NET";

   Byte hexByte[] = {Convert::ToByte(100),
      Convert::ToByte(50)};
   myGroup->GroupNumber = hexByte;

   DateTime myDate = DateTime(2001,1,10);
   myGroup->Today = myDate;

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

int main()
{
   SerializeObject(S"Attributes.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, .NET Compact Framework

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

See Also

XmlAttributeAttribute Members | System.Xml.Serialization Namespace

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