FileSystemWatcher.Filter 属性

定义

获取或设置用于确定在目录中监视哪些文件的筛选器字符串。

public:
 property System::String ^ Filter { System::String ^ get(); void set(System::String ^ value); };
public string Filter { get; set; }
[System.ComponentModel.TypeConverter("System.Diagnostics.Design.StringValueConverter, System.Design, Version=1.0.5000.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")]
[System.IO.IODescription("FSW_Filter")]
public string Filter { get; set; }
[System.IO.IODescription("FSW_Filter")]
[System.ComponentModel.TypeConverter("System.Diagnostics.Design.StringValueConverter, System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")]
public string Filter { get; set; }
[System.IO.IODescription("FSW_Filter")]
[System.ComponentModel.SettingsBindable(true)]
[System.ComponentModel.TypeConverter("System.Diagnostics.Design.StringValueConverter, System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")]
public string Filter { get; set; }
[System.ComponentModel.SettingsBindable(true)]
public string Filter { get; set; }
[System.ComponentModel.TypeConverter("System.Diagnostics.Design.StringValueConverter, System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")]
[System.IO.IODescription("File name filter pattern")]
public string Filter { get; set; }
member this.Filter : string with get, set
[<System.ComponentModel.TypeConverter("System.Diagnostics.Design.StringValueConverter, System.Design, Version=1.0.5000.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")>]
[<System.IO.IODescription("FSW_Filter")>]
member this.Filter : string with get, set
[<System.IO.IODescription("FSW_Filter")>]
[<System.ComponentModel.TypeConverter("System.Diagnostics.Design.StringValueConverter, System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")>]
member this.Filter : string with get, set
[<System.IO.IODescription("FSW_Filter")>]
[<System.ComponentModel.SettingsBindable(true)>]
[<System.ComponentModel.TypeConverter("System.Diagnostics.Design.StringValueConverter, System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")>]
member this.Filter : string with get, set
[<System.ComponentModel.SettingsBindable(true)>]
member this.Filter : string with get, set
[<System.ComponentModel.TypeConverter("System.Diagnostics.Design.StringValueConverter, System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")>]
[<System.IO.IODescription("File name filter pattern")>]
member this.Filter : string with get, set
Public Property Filter As String

属性值

String

筛选器字符串。 默认值为“*”。* (监视所有 files.)

属性

示例

以下示例创建一个 FileSystemWatcher 用于监视运行时指定的目录。 该组件设置为监视 LastWrite 目录中文本文件的创建、删除或重命名更改的时间 LastAccess 和时间。 如果文件已更改、创建或删除,则文件的路径将打印到控制台。 重命名文件时,旧路径和新路径将打印到控制台。

#include "pch.h"

using namespace System;
using namespace System::IO;

class MyClassCPP
{
public:

    int static Run()
    {
        FileSystemWatcher^ watcher = gcnew FileSystemWatcher("C:\\path\\to\\folder");

        watcher->NotifyFilter = static_cast<NotifyFilters>(NotifyFilters::Attributes
                                                         | NotifyFilters::CreationTime
                                                         | NotifyFilters::DirectoryName
                                                         | NotifyFilters::FileName
                                                         | NotifyFilters::LastAccess
                                                         | NotifyFilters::LastWrite
                                                         | NotifyFilters::Security
                                                         | NotifyFilters::Size);

        watcher->Changed += gcnew FileSystemEventHandler(MyClassCPP::OnChanged);
        watcher->Created += gcnew FileSystemEventHandler(MyClassCPP::OnCreated);
        watcher->Deleted += gcnew FileSystemEventHandler(MyClassCPP::OnDeleted);
        watcher->Renamed += gcnew RenamedEventHandler(MyClassCPP::OnRenamed);
        watcher->Error   += gcnew ErrorEventHandler(MyClassCPP::OnError);

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

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

        return 0;
    }

private:

    static void OnChanged(Object^ sender, FileSystemEventArgs^ e)
    {
        if (e->ChangeType != WatcherChangeTypes::Changed)
        {
            return;
        }
        Console::WriteLine("Changed: {0}", e->FullPath);
    }

    static void OnCreated(Object^ sender, FileSystemEventArgs^ e)
    {
        Console::WriteLine("Created: {0}", e->FullPath);
    }

    static void OnDeleted(Object^ sender, FileSystemEventArgs^ e)
    {
        Console::WriteLine("Deleted: {0}", e->FullPath);
    }

    static void OnRenamed(Object^ sender, RenamedEventArgs^ e)
    {
        Console::WriteLine("Renamed:");
        Console::WriteLine("    Old: {0}", e->OldFullPath);
        Console::WriteLine("    New: {0}", e->FullPath);
    }

    static void OnError(Object^ sender, ErrorEventArgs^ e)
    {
        PrintException(e->GetException());
    }

    static void PrintException(Exception^ ex)
    {
        if (ex != nullptr)
        {
            Console::WriteLine("Message: {0}", ex->Message);
            Console::WriteLine("Stacktrace:");
            Console::WriteLine(ex->StackTrace);
            Console::WriteLine();
            PrintException(ex->InnerException);
        }
    }
};


int main()
{
    MyClassCPP::Run();
}
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

注解

若要监视所有文件中的更改,请将 Filter 属性设置为空字符串 (“”) 。 若要监视特定文件,请将 Filter 属性设置为文件名。 例如,若要监视文件MyDoc.txt中的更改,请将 Filter 属性设置为“MyDoc.txt”。 还可以监视特定类型的文件中的更改。 例如,若要监视任何文本文件中的更改,请将 Filter 属性设置为“*.txt”。 不支持使用多个筛选器,例如“*.txt|*.doc”。

Filter 对象开始接收事件后 FileSystemWatcher ,可以更改该属性。

有关筛选掉不需要的通知的详细信息,请参阅NotifyFilterIncludeSubdirectoriesInternalBufferSize属性。

Filter 接受匹配文件的通配符,如以下示例所示。

筛选器字符串 监视以下文件
*.* 所有文件 (默认) 。 空字符串 (“”) 也会监视所有文件。
*.txt 所有扩展名为“txt”的文件。
*recipe.doc 以“doc”扩展名结尾的所有文件。
win*.xml 以“xml”扩展名开头的所有文件。
Sales*200?.xls 匹配以下内容:

- 销售 7 月 2001.xls
- 8 月 2002.xls 日销售额
- 销售 3 月 2004.xls

但不匹配:

- 11 月 1999.xls 日销售额
MyReport.Doc 仅监视MyReport.doc

适用于

另请参阅