XmlSerializer.UnknownAttribute 事件
重要
一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。 对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。
当 XmlSerializer 在反序列化过程中遇到未知类型的 XML 特性时发生。
public:
event System::Xml::Serialization::XmlAttributeEventHandler ^ UnknownAttribute;public event System.Xml.Serialization.XmlAttributeEventHandler UnknownAttribute;member this.UnknownAttribute : System.Xml.Serialization.XmlAttributeEventHandler Public Custom Event UnknownAttribute As XmlAttributeEventHandler 以下示例打印有关反序列化 XML 文档时遇到的任何未知属性的信息。
#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
{
public:
static void main()
{
Test^ t = gcnew 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{0} {1}", e->Attr->Name, e->Attr->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 );
}
void DeserializeObject( String^ filename )
{
XmlSerializer^ ser = gcnew XmlSerializer( Group::typeid );
// Add a delegate to handle unknown element events.
ser->UnknownAttribute += gcnew XmlAttributeEventHandler( this, &Test::Serializer_UnknownAttribute );
// 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::main();
}
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();
}
}
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("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
默认情况下，在调用 Deserialize 方法后， 会 XmlSerializer 忽略未知类型的 XML 属性。 但是，可以使用此事件来处理此类节点类型。
如果正在反序列化的类的实例包含返回对象数组的 XmlAttribute 字段，并且 XmlAnyAttributeAttribute 已应用于该字段，则不会发生该 UnknownAttribute 事件。 而是将所有未知的 XML 属性收集到 数组中。
| 产品 | 版本 |
|---|---|
| .NET | Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10 |
| .NET Framework | 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
| .NET Standard | 2.0, 2.1 |
