XmlAttributeEventHandler Delegate
Represents the method that handles the UnknownAttribute
Assembly: System.Xml (in System.Xml.dll)
'Declaration Public Delegate Sub XmlAttributeEventHandler ( _ sender As Object, _ e As XmlAttributeEventArgs _ )
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>
Imports System Imports System.IO Imports System.Xml.Serialization Imports System.Xml Imports System.Xml.Schema Imports Microsoft.VisualBasic 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("UnknownAttributes.xml") End Sub Private Sub Serializer_UnknownAttribute _ (sender As Object , e As XmlAttributeEventArgs) Console.WriteLine("Unknown Attribute") Console.WriteLine(ControlChars.Tab & e.Attr.Name + " " & e.Attr.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.UnknownAttribute, _ AddressOf Serializer_UnknownAttribute ' 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
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.