XmlSerializer.UnknownAttribute Event
Definition
Important
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Occurs when the XmlSerializer encounters an XML attribute of unknown type during deserialization.
public:
event System::Xml::Serialization::XmlAttributeEventHandler ^ UnknownAttribute;
public event System.Xml.Serialization.XmlAttributeEventHandler UnknownAttribute;
member this.UnknownAttribute : System.Xml.Serialization.XmlAttributeEventHandler
Public Custom Event UnknownAttribute As XmlAttributeEventHandler
Event Type
Examples
The following example prints information about any unknown attributes encountered while deserializing an XML document.
#using <System.Xml.dll>
#using <System.dll>
using namespace System;
using namespace System::IO;
using namespace System::Xml::Serialization;
using namespace System::Xml;
using namespace System::Xml::Schema;
public ref class Group
{
public:
String^ GroupName;
};
public ref class Test
{
public:
static void main()
{
Test^ t = gcnew Test;
// Deserialize the file containing unknown elements.
t->DeserializeObject( "UnknownAttributes.xml" );
}
private:
void Serializer_UnknownAttribute( Object^ sender, XmlAttributeEventArgs^ e )
{
Console::WriteLine( "Unknown Attribute" );
Console::WriteLine( "\t{0} {1}", e->Attr->Name, e->Attr->InnerXml );
Console::WriteLine( "\t LineNumber: {0}", e->LineNumber );
Console::WriteLine( "\t LinePosition: {0}", e->LinePosition );
Group^ x = dynamic_cast<Group^>(e->ObjectBeingDeserialized);
Console::WriteLine( x->GroupName );
Console::WriteLine( sender );
}
void DeserializeObject( String^ filename )
{
XmlSerializer^ ser = gcnew XmlSerializer( Group::typeid );
// Add a delegate to handle unknown element events.
ser->UnknownAttribute += gcnew XmlAttributeEventHandler( this, &Test::Serializer_UnknownAttribute );
// A FileStream is needed to read the XML document.
FileStream^ fs = gcnew FileStream( filename,FileMode::Open );
Group^ g = dynamic_cast<Group^>(ser->Deserialize( fs ));
fs->Close();
}
};
int main()
{
Test::main();
}
using System;
using System.IO;
using System.Xml.Serialization;
using System.Xml;
using System.Xml.Schema;
public class Group{
public string GroupName;
}
public class Test{
static void Main(){
Test t = new Test();
// Deserialize the file containing unknown elements.
t.DeserializeObject("UnknownAttributes.xml");
}
private void Serializer_UnknownAttribute(object sender, XmlAttributeEventArgs e){
Console.WriteLine("Unknown Attribute");
Console.WriteLine("\t" + e.Attr.Name + " " + e.Attr.InnerXml);
Console.WriteLine("\t LineNumber: " + e.LineNumber);
Console.WriteLine("\t LinePosition: " + e.LinePosition);
Group x = (Group) e.ObjectBeingDeserialized;
Console.WriteLine (x.GroupName);
Console.WriteLine (sender.ToString());
}
private void DeserializeObject(string filename){
XmlSerializer ser = new XmlSerializer(typeof(Group));
// Add a delegate to handle unknown element events.
ser.UnknownAttribute+=new XmlAttributeEventHandler(Serializer_UnknownAttribute);
// A FileStream is needed to read the XML document.
FileStream fs = new FileStream(filename, FileMode.Open);
Group g = (Group) ser.Deserialize(fs);
fs.Close();
}
}
Imports System.IO
Imports System.Xml.Serialization
Imports System.Xml
Imports System.Xml.Schema
Public Class Group
Public GroupName As String
End Class
Public Class Test
Shared Sub Main()
Dim t As Test = new Test()
' Deserialize the file containing unknown elements.
t.DeserializeObject("UnknownAttributes.xml")
End Sub
Private Sub Serializer_UnknownAttribute _
(sender As Object , e As XmlAttributeEventArgs)
Console.WriteLine("Unknown Attribute")
Console.WriteLine(ControlChars.Tab & e.Attr.Name + " " & e.Attr.InnerXml)
Console.WriteLine(ControlChars.Tab & e.LineNumber & ":" & e.LineNumber)
Console.WriteLine(ControlChars.Tab & e.LinePosition & ":" & e.LinePosition)
Dim x As Group = CType( e.ObjectBeingDeserialized, Group)
Console.WriteLine (x.GroupName)
Console.WriteLine (sender.ToString())
End Sub
Private Sub DeserializeObject(filename As String)
Dim ser As XmlSerializer = new XmlSerializer(GetType(Group))
' Add a delegate to handle unknown element events.
AddHandler ser.UnknownAttribute, _
AddressOf Serializer_UnknownAttribute
' A FileStream is needed to read the XML document.
Dim fs As FileStream = new FileStream(filename, FileMode.Open)
Dim g As Group = CType(ser.Deserialize(fs),Group)
fs.Close()
End Sub
End Class
Remarks
By default, after calling the Deserialize method, the XmlSerializer ignores XML attributes of unknown types. However, you can use this event to handle such node types.
If the instance of the class being deserialized contains a field that returns an array of XmlAttribute objects and an XmlAnyAttributeAttribute has been applied to the field, the UnknownAttribute event does not occur. Instead, all unknown XML attributes are collected into the array.
Applies to
See also
- XmlAnyAttributeAttribute
- CanDeserialize(XmlReader)
- Deserialize(Stream)
- UnknownNode
- XmlAttributes
- Introducing XML Serialization
- How to: Specify an Alternate Element Name for an XML Stream
- Controlling XML Serialization Using Attributes
- Examples of XML Serialization
- XML Schema Definition Tool (Xsd.exe)