本文档已存档,并且将不进行维护。

FileSystemWatcher.Changed 事件

当更改指定 Path 中的文件和目录时发生。

命名空间: System.IO
程序集: System(在 system.dll 中)

public event FileSystemEventHandler Changed
/** @event */
public void add_Changed (FileSystemEventHandler value)

/** @event */
public void remove_Changed (FileSystemEventHandler value)

在 JScript 中,可处理由类定义的事件,但无法定义自己的事件。
不适用。

当对所监视的目录中的文件或目录的大小、系统属性、上次写入时间、上次访问时间或安全权限进行更改时,将引发 Changed 事件。

说明注意:

公共文件系统操作可能会引发多个事件。例如,将文件从一个目录移到另一个目录时,可能会引发若干 OnChanged 以及一些 OnCreatedOnDeleted 事件。移动文件是一个包含多个简单操作的复杂操作,因此会引发多个事件。同样,有些应用程序(例如,防病毒软件)可能会导致可由 FileSystemWatcher 检测到的其他文件系统事件。

使用 NotifyFilter 限制处理此事件时引发的通知数。

说明注意:

重命名文件时意外引发 Changed 事件,但重命名目录时不会引发它。若要监视重命名,请使用 Renamed 事件。

public class Watcher
{

    public static void Main()
    {
	Run();

    }

    [PermissionSet(SecurityAction.Demand, Name="FullTrust")]
    public static void Run()
    {
        string[] args = System.Environment.GetCommandLineArgs();
 
        // If a directory is not specified, exit program.
        if(args.Length != 2)
        {
            // Display the proper way to call the program.
            Console.WriteLine("Usage: Watcher.exe (directory)");
            return;
        }

        // Create a new FileSystemWatcher and set its properties.
        FileSystemWatcher watcher = new FileSystemWatcher();
        watcher.Path = args[1];
        /* Watch for changes in LastAccess and LastWrite times, and 
           the renaming of files or directories. */
        watcher.NotifyFilter = NotifyFilters.LastAccess | NotifyFilters.LastWrite 
           | NotifyFilters.FileName | NotifyFilters.DirectoryName;
        // Only watch text files.
        watcher.Filter = "*.txt";

        // Add event handlers.
        watcher.Changed += new FileSystemEventHandler(OnChanged);
        watcher.Created += new FileSystemEventHandler(OnChanged);
        watcher.Deleted += new FileSystemEventHandler(OnChanged);
        watcher.Renamed += new RenamedEventHandler(OnRenamed);

        // Begin watching.
        watcher.EnableRaisingEvents = true;

        // Wait for the user to quit the program.
        Console.WriteLine("Press \'q\' to quit the sample.");
        while(Console.Read()!='q');
    }

    // Define the event handlers.
    private static void OnChanged(object source, FileSystemEventArgs e)
    {
        // Specify what is done when a file is changed, created, or deleted.
       Console.WriteLine("File: " +  e.FullPath + " " + e.ChangeType);
    }

    private static void OnRenamed(object source, RenamedEventArgs e)
    {
        // Specify what is done when a file is renamed.
        Console.WriteLine("File: {0} renamed to {1}", e.OldFullPath, e.FullPath);
    }
}


public class Watcher
{
    public static void main(String[] args1)
    {
	Run();
    } 

    /** @attribute PermissionSet(SecurityAction.Demand, Name="FullTrust")
     */
    public static void Run()
    {
        String args[] = System.Environment.GetCommandLineArgs();

        // If a directory is not specified, exit program.
        if (args.length != 2) {

            // Display the proper way to call the program.
            Console.WriteLine("Usage: Watcher.exe (directory)");
            return;
        }

        // Create a new FileSystemWatcher and set its properties.
        FileSystemWatcher watcher = new FileSystemWatcher();
        watcher.set_Path(args[1]);

        /* Watch for changes in LastAccess and LastWrite times, and 
           the renaming of files or directories.
         */
        watcher.set_NotifyFilter
            (NotifyFilters.LastAccess |NotifyFilters.LastWrite |
            NotifyFilters.FileName | NotifyFilters.DirectoryName);

        // Only watch text files.
        watcher.set_Filter("*.txt");

        // Add event handlers.
        watcher.add_Changed(new FileSystemEventHandler(OnChanged));
        watcher.add_Created(new FileSystemEventHandler(OnChanged));
        watcher.add_Deleted(new FileSystemEventHandler(OnChanged));
        watcher.add_Renamed(new RenamedEventHandler(OnRenamed));

        // Begin watching.
        watcher.set_EnableRaisingEvents(true);

        // Wait for the user to quit the program.
        Console.WriteLine("Press \'q\' to quit the sample.");
        while ((Console.Read() != 'q')) {

        }
    }

    // Define the event handlers.
    private static void OnChanged(Object source,FileSystemEventArgs e)
    {
        // Specify what is done when a file is changed, created, or deleted.
        Console.WriteLine(("File: " + e.get_FullPath() + " " 
            + e.get_ChangeType()));
    } //OnChanged

    private static void OnRenamed(Object source, RenamedEventArgs e)
    {
        // Specify what is done when a file is renamed.
        Console.WriteLine("File: {0} renamed to {1}",
            e.get_OldFullPath(),e.get_FullPath());
    } //OnRenamed
} //Watcher

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

Windows Vista、Microsoft Windows XP SP2 和 Windows Server 2003 SP1 支持 Microsoft .NET Framework 3.0。

.NET Framework

受以下版本支持:3.0、2.0、1.1、1.0
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