XmlNodeChangedEventHandler 委托
定义
表示处理以下事件的方法:NodeChanged、NodeChanging、NodeInserted、NodeInserting、NodeRemoved 和 NodeRemoving。Represents the method that handles NodeChanged, NodeChanging, NodeInserted, NodeInserting, NodeRemoved and NodeRemoving events.
public delegate void XmlNodeChangedEventHandler(System::Object ^ sender, XmlNodeChangedEventArgs ^ e);
public delegate void XmlNodeChangedEventHandler(object sender, XmlNodeChangedEventArgs e);
type XmlNodeChangedEventHandler = delegate of obj * XmlNodeChangedEventArgs -> unit
Public Delegate Sub XmlNodeChangedEventHandler(sender As Object, e As XmlNodeChangedEventArgs)
参数
- sender
- Object
事件源。The source of the event.
包含事件数据的 XmlNodeChangedEventArgs。An XmlNodeChangedEventArgs containing the event data.
- 继承
示例
下面的示例演示如何处理NodeChanged
和NodeInserted
事件。The following example shows how to handle the NodeChanged
and NodeInserted
events.
#using <System.Xml.dll>
using namespace System;
using namespace System::IO;
using namespace System::Xml;
public ref class Sample
{
public:
void Run( String^ args )
{
// Create and load the XML document.
Console::WriteLine( "Loading file {0} ...", args );
XmlDocument^ doc = gcnew XmlDocument;
doc->Load( args );
//Create the event handlers.
doc->NodeChanged += gcnew XmlNodeChangedEventHandler( this, &Sample::MyNodeChangedEvent );
doc->NodeInserted += gcnew XmlNodeChangedEventHandler( this, &Sample::MyNodeInsertedEvent );
// Change the book price.
doc->DocumentElement->LastChild->InnerText = "5.95";
// Add a new element.
XmlElement^ newElem = doc->CreateElement( "style" );
newElem->InnerText = "hardcover";
doc->DocumentElement->AppendChild( newElem );
Console::WriteLine( "\r\nDisplay the modified XML..." );
Console::WriteLine( doc->OuterXml );
}
// Handle the NodeChanged event.
private:
void MyNodeChangedEvent( Object^ /*src*/, XmlNodeChangedEventArgs^ args )
{
Console::Write( "Node Changed Event: <{0}> changed", args->Node->Name );
if ( args->Node->Value != nullptr )
{
Console::WriteLine( " with value {0}", args->Node->Value );
}
else
Console::WriteLine( "" );
}
// Handle the NodeInserted event.
void MyNodeInsertedEvent( Object^ /*src*/, XmlNodeChangedEventArgs^ args )
{
Console::Write( "Node Inserted Event: <{0}> inserted", args->Node->Name );
if ( args->Node->Value != nullptr )
{
Console::WriteLine( " with value {0}", args->Node->Value );
}
else
Console::WriteLine( "" );
}
};
// End class
int main()
{
Sample^ mySample = gcnew Sample;
mySample->Run( "book.xml" );
}
using System;
using System.IO;
using System.Xml;
namespace Microsoft.Samples.Xml
{
public class Sample
{
private const String filename = "book.xml";
public static void Main()
{
Sample mySample = new Sample();
mySample.Run(filename);
}
public void Run(String args)
{
// Create and load the XML document.
Console.WriteLine("Loading file {0} ...", args);
XmlDocument doc = new XmlDocument();
doc.Load(args);
//Create the event handlers.
doc.NodeChanged += new XmlNodeChangedEventHandler(this.MyNodeChangedEvent);
doc.NodeInserted += new XmlNodeChangedEventHandler(this.MyNodeInsertedEvent);
// Change the book price.
doc.DocumentElement.LastChild.InnerText = "5.95";
// Add a new element.
XmlElement newElem = doc.CreateElement("style");
newElem.InnerText = "hardcover";
doc.DocumentElement.AppendChild(newElem);
Console.WriteLine("\r\nDisplay the modified XML...");
Console.WriteLine(doc.OuterXml);
}
// Handle the NodeChanged event.
private void MyNodeChangedEvent(Object source, XmlNodeChangedEventArgs args)
{
Console.Write("Node Changed Event: <{0}> changed", args.Node.Name);
if (args.Node.Value != null)
{
Console.WriteLine(" with value {0}", args.Node.Value);
}
else
Console.WriteLine("");
}
// Handle the NodeInserted event.
private void MyNodeInsertedEvent(Object source, XmlNodeChangedEventArgs args)
{
Console.Write("Node Inserted Event: <{0}> inserted", args.Node.Name);
if (args.Node.Value != null)
{
Console.WriteLine(" with value {0}", args.Node.Value);
}
else
Console.WriteLine("");
}
} // End class
Imports System.IO
Imports System.Xml
Namespace Microsoft.Samples.Xml
Public Class Sample
Private Const filename As String = "book.xml"
Public Shared Sub Main()
Dim mySample As Sample = New Sample()
mySample.Run(filename)
End Sub
Public Sub Run(ByVal args As String)
' Create and load the XML document.
Console.WriteLine("Loading file {0} ...", args)
Dim doc As XmlDocument = New XmlDocument()
doc.Load(args)
'Create the event handlers.
AddHandler doc.NodeChanged, AddressOf MyNodeChangedEvent
AddHandler doc.NodeInserted, AddressOf MyNodeInsertedEvent
' Change the book price.
doc.DocumentElement.LastChild.InnerText = "5.95"
' Add a new element.
Dim newElem As XmlElement = doc.CreateElement("style")
newElem.InnerText = "hardcover"
doc.DocumentElement.AppendChild(newElem)
Console.WriteLine()
Console.WriteLine("Display the modified XML...")
Console.WriteLine(doc.OuterXml)
End Sub
' Handle the NodeChanged event.
Private Sub MyNodeChangedEvent(ByVal source As Object, ByVal args As XmlNodeChangedEventArgs)
Console.Write("Node Changed Event: <{0}> changed", args.Node.Name)
If Not (args.Node.Value Is Nothing) Then
Console.WriteLine(" with value {0}", args.Node.Value)
Else
Console.WriteLine("")
End If
End Sub
' Handle the NodeInserted event.
Private Sub MyNodeInsertedEvent(ByVal source As Object, ByVal args As XmlNodeChangedEventArgs)
Console.Write("Node Inserted Event: <{0}> inserted", args.Node.Name)
If Not (args.Node.Value Is Nothing) Then
Console.WriteLine(" with value {0}", args.Node.Value)
Else
Console.WriteLine("")
End If
End Sub
End Class
End Namespace
该示例使用文件book.xml
作为输入。The example uses the file book.xml
as input.
<!--sample XML fragment-->
<book genre='novel' ISBN='1-861003-78' misc='sale-item'>
<title>The Handmaid's Tale</title>
<price>14.95</price>
</book>
注解
创建XmlNodeChangedEventHandler
委托时, 需要标识用于处理事件的方法。When you create an XmlNodeChangedEventHandler
delegate, you identify the method that handles the event. 若要将事件与事件处理程序关联,请将该委托的一个实例添加到事件中。To associate the event with your event handler, add an instance of the delegate to the event. 除非移除了该委托,否则每当发生该事件时就会调用事件处理程序。The event handler is called whenever the event occurs, unless you remove the delegate. 有关事件处理程序委托的详细信息, 请参阅处理和引发事件。For more information about event handler delegates, see Handling and Raising Events.
扩展方法
GetMethodInfo(Delegate) |
获取指示指定委托表示的方法的对象。Gets an object that represents the method represented by the specified delegate. |