XmlSerializer::UnknownAttribute Event

 

Occurs when the XmlSerializer encounters an XML attribute of unknown type during deserialization.

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

public:
event XmlAttributeEventHandler^ UnknownAttribute {
	void add(XmlAttributeEventHandler^ value);
	void remove(XmlAttributeEventHandler^ value);
}

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.

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();
}

.NET Framework
Available since 1.1
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