FileSystemWatcher.Changed Evento

public:
 event System::IO::FileSystemEventHandler ^ Changed;

[System.IO.IODescription("FSW_Changed")]
public event System.IO.FileSystemEventHandler Changed;

public event System.IO.FileSystemEventHandler Changed;

[<System.IO.IODescription("FSW_Changed")>]
member this.Changed : System.IO.FileSystemEventHandler 

member this.Changed : System.IO.FileSystemEventHandler 

Public Custom Event Changed As FileSystemEventHandler 

Tipo de Evento

Atributos

IODescriptionAttribute

Exemplos

O exemplo seguinte utiliza o Changed evento para mostrar o caminho do ficheiro para a consola sempre que o ficheiro visualizado é alterado.

using System;
using System.IO;

namespace MyNamespace
{
    class MyClassCS
    {
        static void Main()
        {
            using var watcher = new FileSystemWatcher(@"C:\path\to\folder");

            watcher.NotifyFilter = NotifyFilters.Attributes
                                 | NotifyFilters.CreationTime
                                 | NotifyFilters.DirectoryName
                                 | NotifyFilters.FileName
                                 | NotifyFilters.LastAccess
                                 | NotifyFilters.LastWrite
                                 | NotifyFilters.Security
                                 | NotifyFilters.Size;

            watcher.Changed += OnChanged;
            watcher.Created += OnCreated;
            watcher.Deleted += OnDeleted;
            watcher.Renamed += OnRenamed;
            watcher.Error += OnError;

            watcher.Filter = "*.txt";
            watcher.IncludeSubdirectories = true;
            watcher.EnableRaisingEvents = true;

            Console.WriteLine("Press enter to exit.");
            Console.ReadLine();
        }

        private static void OnChanged(object sender, FileSystemEventArgs e)
        {
            if (e.ChangeType != WatcherChangeTypes.Changed)
            {
                return;
            }
            Console.WriteLine($"Changed: {e.FullPath}");
        }

        private static void OnCreated(object sender, FileSystemEventArgs e)
        {
            string value = $"Created: {e.FullPath}";
            Console.WriteLine(value);
        }

        private static void OnDeleted(object sender, FileSystemEventArgs e) =>
            Console.WriteLine($"Deleted: {e.FullPath}");

        private static void OnRenamed(object sender, RenamedEventArgs e)
        {
            Console.WriteLine($"Renamed:");
            Console.WriteLine($"    Old: {e.OldFullPath}");
            Console.WriteLine($"    New: {e.FullPath}");
        }

        private static void OnError(object sender, ErrorEventArgs e) =>
            PrintException(e.GetException());

        private static void PrintException(Exception? ex)
        {
            if (ex != null)
            {
                Console.WriteLine($"Message: {ex.Message}");
                Console.WriteLine("Stacktrace:");
                Console.WriteLine(ex.StackTrace);
                Console.WriteLine();
                PrintException(ex.InnerException);
            }
        }
    }
}

Imports System.IO

Namespace MyNamespace

    Class MyClassVB

        Shared Sub Main()
            Using watcher = New FileSystemWatcher("C:\path\to\folder")
                watcher.NotifyFilter = NotifyFilters.Attributes Or
                                       NotifyFilters.CreationTime Or
                                       NotifyFilters.DirectoryName Or
                                       NotifyFilters.FileName Or
                                       NotifyFilters.LastAccess Or
                                       NotifyFilters.LastWrite Or
                                       NotifyFilters.Security Or
                                       NotifyFilters.Size

                AddHandler watcher.Changed, AddressOf OnChanged
                AddHandler watcher.Created, AddressOf OnCreated
                AddHandler watcher.Deleted, AddressOf OnDeleted
                AddHandler watcher.Renamed, AddressOf OnRenamed
                AddHandler watcher.Error, AddressOf OnError

                watcher.Filter = "*.txt"
                watcher.IncludeSubdirectories = True
                watcher.EnableRaisingEvents = True

                Console.WriteLine("Press enter to exit.")
                Console.ReadLine()
            End Using
        End Sub

        Private Shared Sub OnChanged(sender As Object, e As FileSystemEventArgs)
            If e.ChangeType <> WatcherChangeTypes.Changed Then
                Return
            End If
            Console.WriteLine($"Changed: {e.FullPath}")
        End Sub

        Private Shared Sub OnCreated(sender As Object, e As FileSystemEventArgs)
            Dim value As String = $"Created: {e.FullPath}"
            Console.WriteLine(value)
        End Sub

        Private Shared Sub OnDeleted(sender As Object, e As FileSystemEventArgs)
            Console.WriteLine($"Deleted: {e.FullPath}")
        End Sub

        Private Shared Sub OnRenamed(sender As Object, e As RenamedEventArgs)
            Console.WriteLine($"Renamed:")
            Console.WriteLine($"    Old: {e.OldFullPath}")
            Console.WriteLine($"    New: {e.FullPath}")
        End Sub

        Private Shared Sub OnError(sender As Object, e As ErrorEventArgs)
            PrintException(e.GetException())
        End Sub

        Private Shared Sub PrintException(ex As Exception)
            If ex IsNot Nothing Then
                Console.WriteLine($"Message: {ex.Message}")
                Console.WriteLine("Stacktrace:")
                Console.WriteLine(ex.StackTrace)
                Console.WriteLine()
                PrintException(ex.InnerException)
            End If
        End Sub

    End Class

End Namespace

Observações

O Changed evento é ativado quando são feitas alterações ao tamanho, atributos do sistema, último tempo de escrita, último tempo de acesso ou permissões de segurança de um ficheiro ou diretório no diretório monitorizado.

Use NotifyFilter para restringir o número de notificações geradas quando este evento é tratado.

Ver também

• NotifyFilter
• OnChanged(FileSystemEventArgs)
• SynchronizingObject
• FileSystemEventArgs
• FileSystemEventHandler