Information
The topic you requested is included in another documentation set. For convenience, it's displayed below. Choose Switch to see the topic in its original location.

FileSystemWatcher.FileSystemWatcher() Constructor

Initializes a new instance of the FileSystemWatcher class.

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

public FileSystemWatcher ()
public FileSystemWatcher ()
public function FileSystemWatcher ()
Not applicable.

You cannot watch a remote computer that does not have Windows NT or Windows 2000. You cannot watch a remote Windows NT 4.0 computer from a Windows NT 4.0 computer.

The following table shows initial property values for an instance of FileSystemWatcher.

Property

Initial Value

NotifyFilter

bitwise OR combination of LastWrite, FileName, and DirectoryName

EnableRaisingEvents

false

Filter

"*.*" (Watch all files.)

IncludeSubdirectories

false

InternalBufferSize

8192

Path

empty string ("")

NoteNote:

The component will not watch the specified directory until the Path is set, and EnableRaisingEvents is true.

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

This example uses the System.Diagnostics and System.IO namespaces.

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

  • SecurityAction.LinkDemand  for full trust for the immediate caller. This member cannot be used by partially trusted code.

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

Community Additions

Show: