Monitor a Directory for a New File

Monitor a Directory for a New File

The .NET Framework includes the System.IO.FileSystemWatcher class to listen for operating system events indicating there are file or directory changes. It can be used to monitor when a file is added, deleted, updated, or even renamed. It relies on the implementation of event handlers to decide how each of the scenarios gets handled. This example will let you try your own version.

Code Snippet:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.IO;

namespace FileWatcher

{

    class Program

    {

        static string directoryPath = @"C:\MyDir\";

        static void Main(string[] args)

        {

            // Make sure the directory location exists

            if (!Directory.Exists(directoryPath))

            {

                  Console.WriteLine("The directory '{0}' does not exist.", directoryPath);

                  return;

            }

           

            FileSystemWatcher watcher = new FileSystemWatcher();

            watcher.Path = directoryPath;

            // Specifying the filter types

            watcher.NotifyFilter = NotifyFilters.Size | NotifyFilters.FileName | NotifyFilters.DirectoryName | NotifyFilters.CreationTime;

            watcher.Filter = "*.*";

            // Register the event handlers

            watcher.Changed += new FileSystemEventHandler(watcher_Changed);

            watcher.Created += new FileSystemEventHandler(watcher_Created);

            watcher.Deleted += new FileSystemEventHandler(watcher_Changed);

            watcher.Renamed += new RenamedEventHandler(watcher_Renamed);

            // Enables the events

            watcher.EnableRaisingEvents = true;

            while (true)

            {

                System.Threading.Thread.Sleep(1000);

            }

        }

        /// <summary>

        /// Handles the Changed event of the watcher control.

        /// </summary>

        /// <param name="sender">The source of the event.</param>

        /// <param name="e">The <see cref="System.IO.FileSystemEventArgs"/> instance containing the event data.</param>

        static void watcher_Changed(object sender, FileSystemEventArgs e)

        {

            Console.WriteLine("The file {0} has been changed", e.Name);

        }

        /// <summary>

        /// Handles the Created event of the watcher control.

        /// </summary>

        /// <param name="sender">The source of the event.</param>

        /// <param name="e">The <see cref="System.IO.FileSystemEventArgs"/> instance containing the event data.</param>

        static void watcher_Created(object sender, FileSystemEventArgs e)

        {

            Console.WriteLine("A new file {0} is created", e.Name);

        }

        /// <summary>

        /// Handles the Renamed event of the watcher control.

        /// </summary>

        /// <param name="sender">The source of the event.</param>

        /// <param name="e">The <see cref="System.IO.RenamedEventArgs"/> instance containing the event data.</param>

        static void watcher_Renamed(object sender, RenamedEventArgs e)

        {

            Console.WriteLine("The file {0} has been renamed", e.Name);

        }

    }

}