how to keep track of activities within a folder???

Thanx ... but one more confusion arises that why have u removed the 5 functions (OnChanged,OnCreated ....) ???? aren't they necessary to be used even if we use Windows Applications ????
I m searching for it myself too but is it possible to integrate WindowsApplication with WebApplication?? if yes then how.

The key is this bit of code:
           using (FileSystemWatcher fsw = new FileSystemWatcher())
            {
                fsw.Path = InputDir;
                fsw.Filter = @"*";
                fsw.IncludeSubdirectories = true;
                fsw.NotifyFilter =
                    NotifyFilters.FileName |
                    NotifyFilters.Attributes |
                    NotifyFilters.LastAccess |
                    NotifyFilters.LastWrite |
                    NotifyFilters.Security |
                    NotifyFilters.Size |
                    NotifyFilters.CreationTime |
                    NotifyFilters.DirectoryName;
                fsw.Changed += new FileSystemEventHandler(OnChanged);
                fsw.Created += new FileSystemEventHandler(OnCreated);
                fsw.Deleted += new FileSystemEventHandler(OnDeleted);
                fsw.Renamed += new RenamedEventHandler(OnRenamed);
                fsw.Error += new ErrorEventHandler(OnError);
                fsw.EnableRaisingEvents = true; 

// Removed all the commented out code

                Thread.Sleep(1000);
            }
 
This code is taking the directory that is passed to it and watching for a number of events to be raised.  When any of those events is raised it takes action.  What you'd want to do is put this code into a Windows Service that monitors your folders.  You can't really run this in a web page becuase the page is not always running. 

I want to monitor the activities of all the folders present at "C:\Inetpub\ftproot\san".User can work on any type of files and not only text files.Since we have given 1GB space (lets say) to each user, so user can do anything to utilize this space.
Variable "id" is redirected to this page from previous page and according to this id the respective folder of user is opened in windows explorer.
Now I want to monitor the activites that the user will do in his folder like creating new file, deleting an existing file or editing a file.I want to monitor user's activities because i have to keep track of the space given to the user so tht i can restrict the user to use 1GB space only and not more than that.
Question:
How and where to observe the functionality of this code.I m using ASP.NET and its a web based application.
Explanation of this code would be highly appreciated as i have never used filesystemWatcher.
Many Thanks
using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Threading;
using System.Diagnostics;

public partial class _Default : System.Web.UI.Page
{
    DAL conn;
    string connection;
    string id = string.Empty;
  
    protected void Page_Load(object sender, EventArgs e)
    {
        connection = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\Documents and Settings\\project\\Desktop\\BE prj\\dbsan.mdb;Persist Security Info=False";
        conn = new DAL(connection);
              
        ////*** Opening Respective Folder of a User ***////
       
        DirectoryInfo directories = new DirectoryInfo(@"C:\\Inetpub\\ftproot\\san\\");
        //DirectoryInfo directories = new DirectoryInfo(@"C:\");
        DirectoryInfo[] folderList = directories.GetDirectories();
       
       
        if (Request.QueryString["id"] != null)
            id = Request.QueryString["id"];
        string path = Path.Combine(@"C:\\Inetpub\\ftproot\\san\\", id);
        int folder_count = folderList.Length;
        for (int j = 0; j < folder_count; j++)
            if (Convert.ToString(folderList[j]) == id)
            {
                Process p = new Process();
                p.StartInfo.FileName = path;
                p.Start();
            }

        ClsFileSystemWatcher FSysWatcher = new ClsFileSystemWatcher();
        FSysWatcher.FileWatcher(path);
    }

    public class ClsFileSystemWatcher
    {
        public void FileWatcher(string InputDir)
        {
            using (FileSystemWatcher fsw = new FileSystemWatcher())
            {
                fsw.Path = InputDir;
                fsw.Filter = @"*";
                fsw.IncludeSubdirectories = true;
                fsw.NotifyFilter =
                    NotifyFilters.FileName |
                    NotifyFilters.Attributes |
                    NotifyFilters.LastAccess |
                    NotifyFilters.LastWrite |
                    NotifyFilters.Security |
                    NotifyFilters.Size |
                    NotifyFilters.CreationTime |
                    NotifyFilters.DirectoryName;
                fsw.Changed += new FileSystemEventHandler(OnChanged);
                fsw.Created += new FileSystemEventHandler(OnCreated);
                fsw.Deleted += new FileSystemEventHandler(OnDeleted);
                fsw.Renamed += new RenamedEventHandler(OnRenamed);
                fsw.Error += new ErrorEventHandler(OnError);
                fsw.EnableRaisingEvents = true;
                //string strOldFile = InputDir + "OldFile.txt";
                //string strNewFile = InputDir + "CreatedFile.txt";
                //// Making changes in existing file
                //using (FileStream stream = File.Open(strOldFile, FileMode.Append))
                //{
                //    StreamWriter sw = new StreamWriter(stream);
                //    sw.Write("Appending new line in Old File");
                //    sw.Flush();
                //    sw.Close();
                //}
                //// Writing new file on FileSystem
                //using (FileStream stream = File.Create(strNewFile))
                //{
                //    StreamWriter sw = new StreamWriter(stream);
                //    sw.Write("Writing First line into the File");
                //    sw.Flush();
                //    sw.Close();
                //}
                //File.Delete(strOldFile);
                //File.Delete(strNewFile);

                // Minimum time given to event handler to track new events raised by the filesystem.
                Thread.Sleep(1000);
            }
        }
        public static void OnChanged(object source, FileSystemEventArgs e)
        {
            Console.WriteLine("File " + e.FullPath + " :" + e.ChangeType);
        }
        public static void OnDeleted(object source, FileSystemEventArgs e)
        {
            Console.WriteLine("File " + e.FullPath + " :" + e.ChangeType);
        }
        public static void OnCreated(object source, FileSystemEventArgs e)
        {
            Console.WriteLine("File " + e.FullPath + " :" + e.ChangeType);
        }
        public static void OnRenamed(object source, RenamedEventArgs e)
        {
            Console.WriteLine("File " + e.OldFullPath + " [Changed to] " + e.FullPath);
        }
        public static void OnError(object source, ErrorEventArgs e)
        {
            Console.WriteLine("Error " + e.ToString());
        }
    }
   
}

What I would do is create a helper service that does the work for you and maintains the information you want in a database table or something, depends on your needs I guess.  Here is a post that has the info you will need to get started, basically you'll want a service that sits and listens for file change notifications on the folders and then takes appropriate action:
http://blogs.msdn.com/b/rakkimk/archive/2007/08/01/c-trapping-file-change-notifications-windows-form-example.aspx