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FileSystemWatcher.Path Property

Gets or sets the path of the directory to watch.

Namespace: System.IO
Assembly: System (in system.dll)

[TypeConverterAttribute("System.Diagnostics.Design.StringValueConverter, System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")] 
public string Path { get; set; }
/** @property */
public String get_Path ()

/** @property */
public void set_Path (String value)

public function get Path () : String

public function set Path (value : String)

Not applicable.

Property Value

The path to monitor. The default is an empty string ("").

Exception typeCondition

ArgumentException

The specified path does not exist or could not be found.

-or-

The specified path contains wildcard characters.

-or-

The specified path contains invalid path characters.

This is a fully qualified path to a directory. If the IncludeSubdirectories property is true, this directory is the root at which the system watches for changes; otherwise it is the only directory watched. To watch a specific file, set the Path property to the fully qualified, correct directory, and the Filter property to the file name.

The Path property supports Universal Naming Convention (UNC) paths.

NoteNote:

This property must be set before the component can watch for changes.

When a directory is renamed, the FileSystemWatcher automatically reattaches itself to the newly renamed item. For example, if you set the Path property to "C:\My Documents" and then manually rename the directory to "C:\Your Documents", the component continues listening for change notifications on the newly renamed directory. However, when you ask for the Path property, it contains the old path. This happens because the component determines what directory watches based on the handle, rather than the name of the directory. Renaming does not affect the handle. So, if you destroy the component, and then recreate it without updating the Path property, your application will fail because the directory no longer exists.

The following example creates a FileSystemWatcher to watch the directory specified at run time. The component is set to watch for changes in LastWrite and LastAccess time, the creation, deletion, or renaming of text files in the directory. If a file is changed, created, or deleted, the path to the file prints to the console. When a file is renamed, the old and new paths print to the console.

Use the System.Diagnostics and System.IO namespaces for this example.

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 Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0
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