XmlNodeChangedEventArgs 會封裝傳遞至 XmlDocument 對象上註冊之事件處理程式的自變數，以處理事件。 下表提供了事件及其觸發時間的描述。
| 事件 | 引發 |
|---|---|
| NodeInserting | 當屬於目前文件的節點即將插入另一個節點時。 |
| NodeInserted | 當屬於目前文件的節點已插入另一個節點時。 |
| NodeRemoving | 當屬於此文件的節點即將從檔中移除時。 |
| NodeRemoved | 當屬於此文件的節點已從其父節點中移除時。 |
| NodeChanging | 當節點的值即將變更時。 |
| NodeChanged | 當節點的值已變更時。 |
備註
如果 XmlDataDocument 記憶體使用量已完全優化為使用 DataSet 記憶體，則對基礎 DataSet 進行變更時，XmlDataDocument 可能不會引發上述任何事件。 如果您需要這些事件，您必須遍歷整個 XmlDocument 一次，這會導致記憶體使用未能完全優化。
下列程式代碼範例示範如何定義事件處理程式，以及如何將事件處理程式新增至事件。
' Attach the event handler, NodeInsertedHandler, to the NodeInserted
' event.
Dim doc as XmlDocument = new XmlDocument()
Dim XmlNodeChgEHdlr as XmlNodeChangedEventHandler = new XmlNodeChangedEventHandler(addressof MyNodeChangedEvent)
AddHandler doc.NodeInserted, XmlNodeChgEHdlr
Dim n as XmlNode = doc.CreateElement( "element" )
Console.WriteLine( "Before Event Inserting" )
' This is the point where the new node is being inserted in the tree,
' and this is the point where the NodeInserted event is raised.
doc.AppendChild( n )
Console.WriteLine( "After Event Inserting" )
' Define the event handler that handles the NodeInserted event.
sub NodeInsertedHandler(src as Object, args as XmlNodeChangedEventArgs)
Console.WriteLine("Node " + args.Node.Name + " inserted!!")
end sub
// Attach the event handler, NodeInsertedHandler, to the NodeInserted
// event.
XmlDocument doc = new XmlDocument();
doc.NodeInserted += new XmlNodeChangedEventHandler(NodeInsertedHandler);
XmlNode n = doc.CreateElement( "element" );
Console.WriteLine( "Before Event Inserting" );
// This is the point where the new node is being inserted in the tree,
// and this is the point where the NodeInserted event is raised.
doc.AppendChild( n );
Console.WriteLine( "After Event Inserting" );
// Define the event handler that handles the NodeInserted event.
void NodeInsertedHandler(Object src, XmlNodeChangedEventArgs args)
{
Console.WriteLine("Node " + args.Node.Name + " inserted!!");
}
某些 XML 文件物件模型 (DOM) 操作是複合操作，可能會導致觸發多個事件。 例如，AppendChild 可能也必須從其先前的父節點移除要附加的節點。 在此情況下，您會看到 NodeRemoved 事件先引發，後面接著 NodeInserted 事件。 設定 InnerXml 之類的作業可能會導致多個事件。
下列程式代碼範例示範如何建立事件處理程序和處理 NodeInserted 事件。
Imports System
Imports System.IO
Imports System.Xml
Imports Microsoft.VisualBasic
Public Class Sample
Private Const filename As String = "books.xml"
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.
Dim XmlNodeChgEHdlr As XmlNodeChangedEventHandler = New XmlNodeChangedEventHandler(AddressOf MyNodeChangedEvent)
Dim XmlNodeInsertEHdlr As XmlNodeChangedEventHandler = New XmlNodeChangedEventHandler(AddressOf MyNodeInsertedEvent)
AddHandler doc.NodeChanged, XmlNodeChgEHdlr
AddHandler doc.NodeInserted, XmlNodeInsertEHdlr
' 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(Chr(13) + Chr(10) + "Display the modified XML...")
Console.WriteLine(doc.OuterXml)
End Sub
' Handle the NodeChanged event.
Public Sub MyNodeChangedEvent(ByVal src 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.
Public Sub MyNodeInsertedEvent(ByVal src 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 class
using System;
using System.IO;
using System.Xml;
public class Sample
{
private const String filename = "books.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.
public void MyNodeChangedEvent(Object src, 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.
public void MyNodeInsertedEvent(Object src, 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
如需詳細資訊，請參閱 XmlNodeChangedEventArgs 和 XmlNodeChangedEventHandler。
