FileSystemWatcher.Changed イベント

定義

指定した Path のファイルまたはディレクトリが変更されたときに発生します。Occurs when a file or directory in the specified Path is changed.

public:
 event System::IO::FileSystemEventHandler ^ Changed;
public event System.IO.FileSystemEventHandler Changed;
[System.IO.IODescription("FSW_Changed")]
public event System.IO.FileSystemEventHandler Changed;
[System.IO.IODescription("Occurs when a file/directory change matches the filter")]
public event System.IO.FileSystemEventHandler Changed;
member this.Changed : System.IO.FileSystemEventHandler 
[<System.IO.IODescription("FSW_Changed")>]
member this.Changed : System.IO.FileSystemEventHandler 
[<System.IO.IODescription("Occurs when a file/directory change matches the filter")>]
member this.Changed : System.IO.FileSystemEventHandler 
Public Custom Event Changed As FileSystemEventHandler 

イベントの種類

FileSystemEventHandler
属性

次の例では、イベントを使用して、 Changed 監視対象のファイルが変更されるたびにコンソールへのファイルパスを表示します。The following example uses the Changed event to display the file path to the console whenever the watched file is changed.

#using <System.dll>

using namespace System;
using namespace System::IO;
using namespace System::Security::Permissions;

public ref class Watcher
{
private:
   // Define the event handlers.
   static void OnChanged( Object^ /*source*/, FileSystemEventArgs^ e )
   {
      // Specify what is done when a file is changed, created, or deleted.
      Console::WriteLine( "File: {0} {1}", e->FullPath, e->ChangeType );
   }

   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:
   [PermissionSet(SecurityAction::Demand, Name="FullTrust")]
   int static run()
   {
      array<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 0;
      }

      // Create a new FileSystemWatcher and set its properties.
      FileSystemWatcher^ watcher = gcnew FileSystemWatcher;
      watcher->Path = args[ 1 ];

      /* Watch for changes in LastAccess and LastWrite times, and 
          the renaming of files or directories. */
      watcher->NotifyFilter = static_cast<NotifyFilters>(NotifyFilters::LastAccess |
            NotifyFilters::LastWrite | NotifyFilters::FileName | NotifyFilters::DirectoryName);

      // Only watch text files.
      watcher->Filter = "*.txt";

      // Add event handlers.
      watcher->Changed += gcnew FileSystemEventHandler( Watcher::OnChanged );
      watcher->Created += gcnew FileSystemEventHandler( Watcher::OnChanged );
      watcher->Deleted += gcnew FileSystemEventHandler( Watcher::OnChanged );
      watcher->Renamed += gcnew RenamedEventHandler( Watcher::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' );

      return 0;
   }
};

int main() {
   Watcher::run();
}
using System;
using System.IO;
using System.Security.Permissions;

public class Watcher
{
    public static void Main()
    {
        Run();
    }

    [PermissionSet(SecurityAction.Demand, Name = "FullTrust")]
    private static void Run()
    {
        string[] args = 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.
        using (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 += OnChanged;
            watcher.Created += OnChanged;
            watcher.Deleted += OnChanged;
            watcher.Renamed += 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: {e.OldFullPath} renamed to {e.FullPath}");
}
Imports System.IO
Imports System.Security.Permissions

Public Class Watcher

    Public Shared Sub Main()

        Run()

    End Sub

    <PermissionSet(SecurityAction.Demand, Name:="FullTrust")>
    Private Shared Sub Run()

        Dim args() As String = Environment.GetCommandLineArgs()

        ' If a directory is not specified, exit the program.
        If args.Length <> 2 Then
            ' Display the proper way to call the program.
            Console.WriteLine("Usage: Watcher.exe (directory)")
            Return
        End If

        ' Create a new FileSystemWatcher and set its properties.
        Using watcher As 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 _
                                 Or NotifyFilters.LastWrite _
                                 Or NotifyFilters.FileName _
                                 Or NotifyFilters.DirectoryName)

            ' Only watch text files.
            watcher.Filter = "*.txt"

            ' Add event handlers.
            AddHandler watcher.Changed, AddressOf OnChanged
            AddHandler watcher.Created, AddressOf OnChanged
            AddHandler watcher.Deleted, AddressOf OnChanged
            AddHandler watcher.Renamed, AddressOf OnRenamed

            ' Begin watching.
            watcher.EnableRaisingEvents = True

            ' Wait for the user to quit the program.
            Console.WriteLine("Press 'q' to quit the sample.")
            While Chr(Console.Read()) <> "q"c
            End While
        End Using
    End Sub

    ' Define the event handlers.
    Private Shared Sub OnChanged(source As Object, e As FileSystemEventArgs)
        ' Specify what is done when a file is changed, created, or deleted.
        Console.WriteLine($"File: {e.FullPath} {e.ChangeType}")
    End Sub

    Private Shared Sub OnRenamed(source As Object, e As RenamedEventArgs)
        ' Specify what is done when a file is renamed.
        Console.WriteLine($"File: {e.OldFullPath} renamed to {e.FullPath}")
    End Sub

End Class

注釈

イベントは、 Changed 監視されているディレクトリ内のファイルまたはディレクトリのサイズ、システム属性、最終書き込み時刻、最終アクセス時刻、またはセキュリティアクセス許可が変更されたときに発生します。The Changed event is raised when changes are made to the size, system attributes, last write time, last access time, or security permissions of a file or directory in the directory being monitored.

注意

一般的なファイルシステム操作では、複数のイベントが発生する可能性があります。Common file system operations might raise more than one event. たとえば、あるディレクトリから別のディレクトリにファイルを移動すると、いくつかの OnChanged OnCreated OnDeleted イベントとイベントが発生する可能性があります。For example, when a file is moved from one directory to another, several OnChanged and some OnCreated and OnDeleted events might be raised. ファイルの移動は、複数の単純な操作で構成される複雑な操作であるため、複数のイベントが発生します。Moving a file is a complex operation that consists of multiple simple operations, therefore raising multiple events. 同様に、一部のアプリケーション (ウイルス対策ソフトウェアなど) によって、によって検出された追加のファイルシステムイベントが発生する可能性があり FileSystemWatcher ます。Likewise, some applications (for example, antivirus software) might cause additional file system events that are detected by FileSystemWatcher.

NotifyFilterこのイベントが処理されるときに発生する通知の数を制限するには、を使用します。Use NotifyFilter to restrict the number of notifications raised when this event is handled.

注意

この Changed イベントは、ファイルの名前が変更されたときに予期せず発生しますが、ディレクトリの名前が変更されたときには発生しません。The Changed event is raised unexpectedly when a file is renamed, but is not raised when a directory is renamed. 名前の変更を監視するには、イベントを使用し Renamed ます。To watch for renaming, use the Renamed event.

注意

Changed他のイベントに関連してイベントが発生する順序は、 FileSystemWatcher プロパティがではない場合に変更される可能性があり SynchronizingObject null ます。The order in which the Changed event is raised in relation to the other FileSystemWatcher events may change when the SynchronizingObject property is not null.

適用対象

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