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XmlAttributeEventHandler Delegate

Represents the method that handles the UnknownAttribute

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

public delegate void XmlAttributeEventHandler(
	Object sender,
	XmlAttributeEventArgs e
)

Parameters

sender
Type: System.Object

The source of the event.

e
Type: System.Xml.Serialization.XmlAttributeEventArgs

An XmlAttributeEventArgs that contains the event data.

When you create an XmlAttributeEventHandler delegate, you identify the method that handles the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about event handler delegates, see Events and Delegates.

The UnknownAttribute event occurs only when an object is being deserialized with the Deserialize method.

The following example deserializes a class named Group from a file named UnknownAttributes.xml. Whenever an element is found in the file that has no corresponding member in the class, the UnknownAttribute event occurs. To try the example, paste the following XML code into a file named UnknownAttributes.xml.

 <?xml version="1.0" encoding="utf-8"?>
 <Group xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" GroupType = 'Technical' GroupNumber = '42' GroupBase = 'Red'>
   <GroupName>MyGroup</GroupName>
 </Group>
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();
   	}
}
#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::Xml;
using namespace System::Xml::Schema;

public __gc class Group{
public:
   String* GroupName;
};

public __gc class Test{
public:
   static void main(){
      Test* t = new Test();
      // Deserialize the file containing unknown elements.
      t->DeserializeObject(S"UnknownAttributes.xml");
   }
private:
   void Serializer_UnknownAttribute(Object* sender, XmlAttributeEventArgs* e){
      Console::WriteLine(S"Unknown Attribute");
      Console::WriteLine(S"\t{0} {1}", e->Attr->Name, e->Attr->InnerXml);
      Console::WriteLine(S"\t LineNumber: {0}", __box(e->LineNumber));
      Console::WriteLine(S"\t LinePosition: {0}", __box(e->LinePosition));

      Group* x  = dynamic_cast<Group*> (e->ObjectBeingDeserialized);
      Console::WriteLine (x->GroupName);
      Console::WriteLine (sender);
   }
private:
   void DeserializeObject(String* filename){
      XmlSerializer* ser = new XmlSerializer(__typeof(Group));
      // Add a delegate to handle unknown element events.
      ser->UnknownAttribute+=new XmlAttributeEventHandler(this, &Test::Serializer_UnknownAttribute);
      // A FileStream is needed to read the XML document.
      FileStream* fs = new FileStream(filename, FileMode::Open);
      Group* g = dynamic_cast<Group*> (ser->Deserialize(fs));
      fs->Close();
   }
};

int main()
{
   Test::main();
}

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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