System.Xml.Serialization.XmlElementEventHandler Delegate

Summary

Represents the method that will handle the XmlSerializer.UnknownElement event of an XmlSerializer.

C# Syntax:

[Serializable] public delegate void XmlElementEventHandler(object sender, XmlElementEventArgs e);

When you create an XmlElementEventHandler delegate, you identify the method that will handle 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 the conceptual topic at MSDN: eventsdelegates.

The XmlSerializer.UnknownElement event can occur only when you call the XmlSerializer.Deserialize method.

The following example deserializes a class named Group from a file named UnknownElements.xml. Whenever an element is found in the file that has no corresponding member in the class, the XmlSerializer.UnknownElement event occurs. To try the example, paste the XML code below into a file named 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;
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();
   	}
}

    

System.Xml.Serialization Namespace

Hierarchy:

• System.Object
• System.Delegate
• System.MulticastDelegate
• System.Xml.Serialization.XmlElementEventHandler

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