XmlSerializer.UnknownElement Event
Assembly: System.Xml (in system.xml.dll)
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.
Note: |
|---|
| If the XmlAnyElementAttribute is applied to a field that returns an array of XmlElement objects, all unknown elements are collected in the array. In that case, the UnknownElement event does not occur. |
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 UnknownElement event occurs. To try the example, paste the following XML code 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(); } }
import System.*;
import System.IO.*;
import System.Xml.Serialization.*;
import System.Xml.*;
import System.Xml.Schema.*;
public class Group
{
public String GroupName;
} //Group
public class Test
{
public static void main(String[] args)
{
Test t = new Test();
// Deserialize the file containing unknown elements.
t.DeserializeObject("UnknownElements.xml");
} //main
private void Serializer_UnknownElement(Object sender,
XmlElementEventArgs e)
{
Console.WriteLine("Unknown Element");
Console.WriteLine("\t" + e.get_Element().get_Name() + " "
+ e.get_Element().get_InnerXml());
Console.WriteLine("\t LineNumber: " + e.get_LineNumber());
Console.WriteLine("\t LinePosition: " + e.get_LinePosition());
Group x = (Group)(e.get_ObjectBeingDeserialized());
Console.WriteLine(x.GroupName);
Console.WriteLine(sender.ToString());
} //Serializer_UnknownElement
private void DeserializeObject(String fileName)
{
XmlSerializer ser = new XmlSerializer(Group.class.ToType());
// Add a delegate to handle unknown element events.
ser.add_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();
} //DeserializeObject
} //Test
Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.Reference
XmlSerializer ClassXmlSerializer Members
System.Xml.Serialization Namespace
XmlAnyElementAttribute
UnknownNode
XmlSerializer.UnknownAttribute Event
XmlAttributes
Other Resources
Introducing XML SerializationHow 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)
Note: