File System Watcher does not fire when more than one file

Hesham Hassanein

10y2.3kC#

Hello,

I have a problem with File System Watcher, It does not fire when i create more than 1 file in the directory i am watching. It only works for 1 file, When 2 or more are copied into the directory at the same time. It does not work. It only sees 1 file.

I am doing 2 event handlers. 1 is onCreated and 1 is onChanged, In the Oncreated i add the files to a queue and call the function which does the process of the collected files and in OnChanged i delete one of the files in the list if it exists, If it does not exist, then do nothing.

What can be the problem in this code. Do i have to work with threading to make watcher sees this fast change in the directory or what?. Thanks in Advance. Here is the code

static void watch()
{
// Create a new FileSystemWatcher and set its properties.
FileSystemWatcher watcher = new FileSystemWatcher();
watcher.Path = @"Q:\New_Folder";
watcher.NotifyFilter = NotifyFilters.LastAccess | NotifyFilters.LastWrite | NotifyFilters.FileName | NotifyFilters.DirectoryName;
watcher.Filter = "*.DAT";
watcher.InternalBufferSize = 64000;
watcher.Created += new FileSystemEventHandler(watcher_Created);
watcher.Changed += new FileSystemEventHandler(OnChanged);
watcher.EnableRaisingEvents = true;
Console.WriteLine("Watching Directory for New Files. To break the process Press \'q\'");
while(Console.Read()!='q');
}
static void watcher_Created(object source, FileSystemEventArgs e)
{
// Specify what is done when a file is created
Console.WriteLine("File: " + e.FullPath + " " + e.ChangeType);
SomeGlobalVariables.queuenames.Enqueue(e.FullPath);
// SomeGlobalVariables.filenameslist.ForEach(Console.WriteLine);
foreach (string number in SomeGlobalVariables.queuenames)
{
Console.WriteLine(number);
}
foreach (var filenames in SomeGlobalVariables.queuenames)
{
var fileName = filenames;
var Name_File = Path.GetFileName(fileName).Replace(".DAT","").Remove(0,6);
var tempfilepath = (@"C:\Users\" + Name_File + ".CSV");
Console.WriteLine(fileName);
ReadData(tempfilepath, fileName);
}
}
static void OnChanged(object source, FileSystemEventArgs e)
{
// Specify what is done when a file is changed
//Console.WriteLine("File: " + e.FullPath + " " + e.ChangeType);
if (!SomeGlobalVariables.queuenames.Contains(e.FullPath))
{
Console.WriteLine("The file is not in the list");
Console.ReadKey();
}
else if (SomeGlobalVariables.queuenames.Contains(e.FullPath))
{
var last_item = SomeGlobalVariables.queuenames.Last();
SomeGlobalVariables.filenameslist.Remove(last_item);
Console.WriteLine("deleted");
foreach (string number in SomeGlobalVariables.queuenames)
{
Console.WriteLine(number);
}
}
}

4 Replies

Know the answer? Post it — somebody with the same question will find it here.

Madhanmohan Devarajan10y ago
For error 2 :static void Watch()change it to static Watch(), simply remove void from the method.
For error 1 : In the place of declarationprivate System.Timers.Timer processTimer and not the Threading one;
Madhanmohan Devarajan10y ago
Here is the code what you need to do
private void ProcessQueue()
{
List list = new List();
try
{
Console.WriteLine("Processing queue, " + filePaths.Count + " files created:");
rwlock.EnterReadLock();
foreach (var filepath in filePaths)
{

var fileName = filepath ;
var Name_File = Path.GetFileName(fileName).Replace(".DAT","").Remove(0,6);
var tempfilepath = (@"C:\Users\" + Name_File + ".CSV");
Console.WriteLine(fileName);

Program.ReadData(tempfilepath,fileName); // To call the static method ReadData from Program class
// comment this: ReadData(tempfilepath, fileName);

}
}
finally
{
if (processTimer != null)
{
processTimer.Stop();
processTimer.Dispose();
processTimer = null;
OnFileListCreated(new FileListEventArgs { FileList = filePaths });
filePaths.Clear();
}
rwlock.ExitReadLock();
}
}
Madhanmohan Devarajan10y ago
You can paste the ReadData() method just below thevoid watcher_Created(object sender, FileSystemEventArgs e) or create an instance for the class that contains the ReadData() method inside the ProcessQueue() method.
Madhanmohan Devarajan10y ago
Please try this, it may work for you. Because in your code there is no option for timer to wait and collect more than one file created. You are trying to get the list of files created on one file created event and that is the reason why it always gives you first file details.
Code:
public class FileListEventArgs : EventArgs
{
public List FileList { get; set; }
}
public class Watch
{
private List filePaths;
private ReaderWriterLockSlim rwlock;
private Timer processTimer;
public event EventHandler FileListCreated;
public void OnFileListCreated(FileListEventArgs e)
{
if (FileListCreated != null)
FileListCreated(this, e);
}
static void Watch()
{
filePaths = new List();
rwlock = new ReaderWriterLockSlim();
FileSystemWatcher watcher = new FileSystemWatcher();
watcher.Filter = "*.*";
//watcher.Created += watcher_FileCreated;
watcher.Created += new FileSystemEventHandler(watcher_Created);
// watcher.Changed += new FileSystemEventHandler(OnChanged);

watcher.Path = @"Q:\New_Folder";
watcher.IncludeSubdirectories = true;
watcher.EnableRaisingEvents = true;
watcher.InternalBufferSize = 64000;
}
private void ProcessQueue()
{
List list = new List();
try
{
Console.WriteLine("Processing queue, " + filePaths.Count + " files created:");
rwlock.EnterReadLock();
foreach (var filepath in filePaths)
{

var fileName = filepath ;
var Name_File = Path.GetFileName(fileName).Replace(".DAT","").Remove(0,6);
var tempfilepath = (@"C:\Users\" + Name_File + ".CSV");
Console.WriteLine(fileName);

ReadData(tempfilepath, fileName);

}
}
finally
{
if (processTimer != null)
{
processTimer.Stop();
processTimer.Dispose();
processTimer = null;
OnFileListCreated(new FileListEventArgs { FileList = filePaths });
filePaths.Clear();
}
rwlock.ExitReadLock();
}
}
void watcher_Created(object sender, FileSystemEventArgs e)
{
try
{
rwlock.EnterWriteLock();
filePaths.Add(e.FullPath);
if (processTimer == null)
{
// First file, start timer.
processTimer = new Timer(2000);
processTimer.Elapsed += (o, ee) => ProcessQueue();
processTimer.Start();
}
else
{
// Subsequent file, reset timer.
processTimer.Stop();
processTimer.Start();
}
}

finally
{
rwlock.ExitWriteLock();

}

}