XmlElementEventHandler Delegar

Definição

Namespace:

System.Xml.Serialization

Assembly:

System.Xml.XmlSerializer.dll

Representa o método que manipula o evento UnknownElement de um XmlSerializer.

public delegate void XmlElementEventHandler(System::Object ^ sender, XmlElementEventArgs ^ e);

public delegate void XmlElementEventHandler(object? sender, XmlElementEventArgs e);

type XmlElementEventHandler = delegate of obj * XmlElementEventArgs -> unit

Public Delegate Sub XmlElementEventHandler(sender As Object, e As XmlElementEventArgs)

Parâmetros

sender

Object

A fonte do evento.

e

XmlElementEventArgs

Um XmlElementEventArgs que contém os dados do evento.

Exemplos

O exemplo a seguir desserializa uma classe chamada Group de um arquivo chamado UnknownElements.xml. Sempre que um elemento é encontrado no arquivo que não tem nenhum membro correspondente na classe , o UnknownElement evento ocorre. Para experimentar o exemplo, cole o código XML a seguir em um arquivo chamado UnknownElements.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">  
  <GroupName>MyGroup</GroupName>  
  <GroupSize>Large</GroupSize>  
  <GroupNumber>444</GroupNumber>  
  <GroupBase>West</GroupBase>  
</Group>  

#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
{
private:
   void Serializer_UnknownElement( Object^ sender, XmlElementEventArgs^ e )
   {
      Console::WriteLine( "Unknown Element" );
      Console::Write( "\t {0}", e->Element->Name );
      Console::WriteLine( " {0}", e->Element->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 );
   }

public:
   void DeserializeObject( String^ filename )
   {
      XmlSerializer^ ser = gcnew XmlSerializer( Group::typeid );

      // Add a delegate to handle unknown element events.
      ser->UnknownElement += gcnew XmlElementEventHandler( this, &Test::Serializer_UnknownElement );

      // 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^ t = gcnew Test;

   // Deserialize the file containing unknown elements.
   t->DeserializeObject( "UnknownElements.xml" );
}

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("UnknownElements.xml");
   }
   private void Serializer_UnknownElement(object sender, XmlElementEventArgs e){
      Console.WriteLine("Unknown Element");
      Console.WriteLine("\t" + e.Element.Name + " " + e.Element.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.UnknownElement+=new XmlElementEventHandler(Serializer_UnknownElement);
      // 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("UnknownElements.xml")
   End Sub

   Private Sub Serializer_UnknownElement _
   (sender As Object , e As XmlElementEventArgs)
      Console.WriteLine("Unknown Element")
      Console.WriteLine(ControlChars.Tab & e.Element.Name + " " & e.Element.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.UnknownElement, _
      AddressOf Serializer_UnknownElement 
      ' 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

Comentários

Ao criar um XmlElementEventHandler delegado, você identifica o método que manipula o evento. Para associar o evento ao manipulador de eventos, adicione uma instância do delegado ao evento. O manipulador de eventos é chamado sempre que o evento ocorre, a menos que você remova o representante. Para obter mais informações sobre representantes do manipulador de eventos, consulte Manipulando e gerando eventos.

O UnknownElement evento ocorre somente quando você chama o Deserialize método .

Métodos de Extensão

GetMethodInfo(Delegate)

Obtém um objeto que representa o método representado pelo delegado especificado.