FileSystemWatcher.Filter 屬性

定義

命名空間:

System.IO

組件:

netstandard.dll, System.IO.FileSystem.Watcher.dll

來源:

FileSystemWatcher.cs

取得或設定用來判斷目錄中監控哪些檔案的過濾字串。

public:
 property System::String ^ Filter { System::String ^ get(); void set(System::String ^ value); };

public string Filter { get; set; }

member this.Filter : string with get, set

Public Property Filter As String

屬性值

String

篩選字串。 預設為「*.*」（監控所有檔案）。

範例

以下範例建立一個 FileSystemWatcher ，以監控執行時指定的目錄。 元件設定為監控目錄中文字檔的建立、刪除或重新命名時間的變化LastWriteLastAccess。 如果檔案被更改、建立或刪除，該檔案的路徑會印到主控台。 當檔案被重新命名時，舊路徑和新路徑會印到主控台。

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

備註

要監控所有檔案的變更，請將屬性設 Filter 為空字串（“”）。 若要監看特定檔案，請將 Filter 屬性設定為檔名。 例如，若要監看檔案 MyDoc.txt中的變更，請將 Filter 屬性設定為 “MyDoc.txt”。 您也可以監看特定類型的檔案變更。 例如，要注意任何文字檔案的變化，將屬性設 Filter 為「*.txt」。 不支援使用多重篩選器，例如「*.txt|*.doc」。

Filter該屬性可在物件開始接收事件後FileSystemWatcher更改。

欲了解更多關於過濾不想要通知的資訊，請參閱 NotifyFilter、 IncludeSubdirectories和 InternalBufferSize 屬性。

Filter 接受匹配檔案的萬用字元，如下範例所示。

濾波器串	觀看以下檔案
*.*	所有檔案（預設）。 空字串（“”）也會監控所有檔案。
*.txt	所有副檔名都是「txt」的檔案。
*recipe.doc	所有以「recipe」結尾、副檔名為「doc」的檔案。
Win*.xml	所有以「win」開頭、副檔名為「xml」的檔案。
銷售額×200？.xls	匹配如下： - 7月 2001.xls 日銷售 - 8月 2002.xls - 三月銷售 2004.xls 但不符合： - 1999.xls 年11月銷售
我的報告。醫生	只看MyReport.doc

另請參閱

• NotifyFilter
• IncludeSubdirectories
• InternalBufferSize