Chapter 21 Monitoring the File System

samuraisxmali · November 9th, 2011, 06:22 AM

in this try it out it don't creates Log.txt file in folder FileLogs and of course don't writes anything in it. can anyone help?

the code is as follows:

Code:

namespace FileWatch
{
    public partial class Form1 : Form
    {
        // File System Watcher object.
        private FileSystemWatcher watcher;
        private delegate void UpdateWatchTextDelegate(string newText);

        public Form1()
        {
            InitializeComponent();

            this.watcher = new FileSystemWatcher();
            this.watcher.Deleted +=
            new FileSystemEventHandler(this.OnDelete);
            this.watcher.Renamed +=
            new RenamedEventHandler(this.OnRenamed);
            this.watcher.Changed +=
            new FileSystemEventHandler(this.OnChanged);
            this.watcher.Created +=
            new FileSystemEventHandler(this.OnCreate);

            //tu ar aris konkretuli (am shemtxvevashi C:\FileLogs) direqtoria 
            //mashin sheiqmneba.
            DirectoryInfo aDir = new DirectoryInfo(@"C:\FileLogs");
            if (!aDir.Exists)
                aDir.Create();
        }

        // Utility method to update watch text.
        public void UpdateWatchText(string newText)
        {
            lblWatch.Text = newText;
        }
        // Define the event handlers.
        public void OnChanged(object source, FileSystemEventArgs e)
        {
            try
            {
                StreamWriter sw =
                new StreamWriter("C:/FileLogs/Log.txt", true);
                sw.WriteLine("File: {0} {1}", e.FullPath,
                e.ChangeType.ToString());
                sw.Close();
                this.BeginInvoke(new UpdateWatchTextDelegate(UpdateWatchText),
                "Wrote change event to log");
            }
            catch (IOException)
            {
                this.BeginInvoke(new UpdateWatchTextDelegate(UpdateWatchText),
                "Error Writing to log");
            }
        }
        public void OnRenamed(object source, RenamedEventArgs e)
        {
            try
            {
                StreamWriter sw =
                new StreamWriter("C:/FileLogs/Log.txt", true);
                sw.WriteLine("File renamed from {0} to {1}", e.OldName,
                e.FullPath);
                sw.Close();
                this.BeginInvoke(new UpdateWatchTextDelegate(UpdateWatchText),
                "Wrote renamed event to log");
            }
            catch (IOException)
            {
                this.BeginInvoke(new UpdateWatchTextDelegate(UpdateWatchText),
                "Error Writing to log");
            }
        }

        public void OnDelete(object source, FileSystemEventArgs e)
        {
            try
            {
                StreamWriter sw =
                new StreamWriter("C:/FileLogs/Log.txt", true);
                sw.WriteLine("File: {0} Deleted", e.FullPath);
                sw.Close();
                this.BeginInvoke(new UpdateWatchTextDelegate(UpdateWatchText),
                "Wrote delete event to log");
            }
            catch (IOException)
            {
                this.BeginInvoke(new UpdateWatchTextDelegate(UpdateWatchText),
                "Error Writing to log");
            }
        }
        public void OnCreate(object source, FileSystemEventArgs e)
        {
            try
            {
                StreamWriter sw =
                new StreamWriter("C:/FileLogs/Log.txt", true);
                sw.WriteLine("File: {0} Created", e.FullPath);
                sw.Close();
                this.BeginInvoke(new UpdateWatchTextDelegate(UpdateWatchText),
                "Wrote create event to log");
            }
            catch (IOException)
            {
                this.BeginInvoke(new UpdateWatchTextDelegate(UpdateWatchText),
                "Error Writing to log");
            }
        }

        private void cmdBrowse_Click(object sender, EventArgs e)
        {
            if (FileDialog.ShowDialog() != DialogResult.Cancel)
            {
                txtLocation.Text = FileDialog.FileName;
                cmdWatch.Enabled = true;
            }
        }

        private void cmdWatch_Click(object sender, EventArgs e)
        {
            watcher.Path = Path.GetDirectoryName(txtLocation.Text);
            watcher.Filter = Path.GetFileName(txtLocation.Text);
            watcher.NotifyFilter = NotifyFilters.LastWrite |
            NotifyFilters.FileName | NotifyFilters.Size;
            lblWatch.Text = "Watching " + txtLocation.Text;
            // Begin watching.
            watcher.EnableRaisingEvents = true;
        }

        
    }
}

ChristianNagel · November 9th, 2011, 11:40 AM

Quote:

Originally Posted by samuraisxmali

in this try it out it don't creates Log.txt file in folder FileLogs and of course don't writes anything in it. can anyone help?

the code is as follows:

Code:

namespace FileWatch
{
    public partial class Form1 : Form
    {
        // File System Watcher object.
        private FileSystemWatcher watcher;
        private delegate void UpdateWatchTextDelegate(string newText);

        public Form1()
        {
            InitializeComponent();

            this.watcher = new FileSystemWatcher();
            this.watcher.Deleted +=
            new FileSystemEventHandler(this.OnDelete);
            this.watcher.Renamed +=
            new RenamedEventHandler(this.OnRenamed);
            this.watcher.Changed +=
            new FileSystemEventHandler(this.OnChanged);
            this.watcher.Created +=
            new FileSystemEventHandler(this.OnCreate);

            //tu ar aris konkretuli (am shemtxvevashi C:\FileLogs) direqtoria 
            //mashin sheiqmneba.
            DirectoryInfo aDir = new DirectoryInfo(@"C:\FileLogs");
            if (!aDir.Exists)
                aDir.Create();
        }

        // Utility method to update watch text.
        public void UpdateWatchText(string newText)
        {
            lblWatch.Text = newText;
        }
        // Define the event handlers.
        public void OnChanged(object source, FileSystemEventArgs e)
        {
            try
            {
                StreamWriter sw =
                new StreamWriter("C:/FileLogs/Log.txt", true);
                sw.WriteLine("File: {0} {1}", e.FullPath,
                e.ChangeType.ToString());
                sw.Close();
                this.BeginInvoke(new UpdateWatchTextDelegate(UpdateWatchText),
                "Wrote change event to log");
            }
            catch (IOException)
            {
                this.BeginInvoke(new UpdateWatchTextDelegate(UpdateWatchText),
                "Error Writing to log");
            }
        }
        public void OnRenamed(object source, RenamedEventArgs e)
        {
            try
            {
                StreamWriter sw =
                new StreamWriter("C:/FileLogs/Log.txt", true);
                sw.WriteLine("File renamed from {0} to {1}", e.OldName,
                e.FullPath);
                sw.Close();
                this.BeginInvoke(new UpdateWatchTextDelegate(UpdateWatchText),
                "Wrote renamed event to log");
            }
            catch (IOException)
            {
                this.BeginInvoke(new UpdateWatchTextDelegate(UpdateWatchText),
                "Error Writing to log");
            }
        }

        public void OnDelete(object source, FileSystemEventArgs e)
        {
            try
            {
                StreamWriter sw =
                new StreamWriter("C:/FileLogs/Log.txt", true);
                sw.WriteLine("File: {0} Deleted", e.FullPath);
                sw.Close();
                this.BeginInvoke(new UpdateWatchTextDelegate(UpdateWatchText),
                "Wrote delete event to log");
            }
            catch (IOException)
            {
                this.BeginInvoke(new UpdateWatchTextDelegate(UpdateWatchText),
                "Error Writing to log");
            }
        }
        public void OnCreate(object source, FileSystemEventArgs e)
        {
            try
            {
                StreamWriter sw =
                new StreamWriter("C:/FileLogs/Log.txt", true);
                sw.WriteLine("File: {0} Created", e.FullPath);
                sw.Close();
                this.BeginInvoke(new UpdateWatchTextDelegate(UpdateWatchText),
                "Wrote create event to log");
            }
            catch (IOException)
            {
                this.BeginInvoke(new UpdateWatchTextDelegate(UpdateWatchText),
                "Error Writing to log");
            }
        }

        private void cmdBrowse_Click(object sender, EventArgs e)
        {
            if (FileDialog.ShowDialog() != DialogResult.Cancel)
            {
                txtLocation.Text = FileDialog.FileName;
                cmdWatch.Enabled = true;
            }
        }

        private void cmdWatch_Click(object sender, EventArgs e)
        {
            watcher.Path = Path.GetDirectoryName(txtLocation.Text);
            watcher.Filter = Path.GetFileName(txtLocation.Text);
            watcher.NotifyFilter = NotifyFilters.LastWrite |
            NotifyFilters.FileName | NotifyFilters.Size;
            lblWatch.Text = "Watching " + txtLocation.Text;
            // Begin watching.
            watcher.EnableRaisingEvents = true;
        }

        
    }
}

What do you want to know? The sample creates a file system watcher to monitor changes on the file system. Step 14 of the excercise on page 720 asks to create a file and add some text to the file using Notepad. Step 15 asks for renaming the previously created file. Have you been successful with the Explorer and Notepad? Then the events from the file system watcher should occur.

samuraisxmali · November 9th, 2011, 02:23 PM

Quote:

Originally Posted by ChristianNagel

What do you want to know? The sample creates a file system watcher to monitor changes on the file system. Step 14 of the excercise on page 720 asks to create a file and add some text to the file using Notepad. Step 15 asks for renaming the previously created file. Have you been successful with the Explorer and Notepad? Then the events from the file system watcher should occur.

yes of course, i did as it is in the book, but it not writes anything in Log.txt file because it (Log.txt file) don't creates at all. the folder you are talking about is TempWatch directory and temp.txt file in it, not FileLogs directory. i said that StreamWriter not works and not creates C:\FileLogs\Log.txt file, which must be created when it is called. i also downloaded the code from this site, but it not works too. i want to know why it not creates Log.txt file in FileLogs directory? maybe somewhere must be the EndInvoke method?
i'm on windows xp sp3.
sorry for bad english and thanks for answer.

ChristianNagel · November 9th, 2011, 07:42 PM

Did you verify if any of the file system watcher event handler is invoked while you run the application? If it is not try changing the Filter property of the FileSystemWatcher to "*.txt" instead of the filename.

Quote:

Originally Posted by samuraisxmali

yes of course, i did as it is in the book, but it not writes anything in Log.txt file because it (Log.txt file) don't creates at all. the folder you are talking about is TempWatch directory and temp.txt file in it, not FileLogs directory. i said that StreamWriter not works and not creates C:\FileLogs\Log.txt file, which must be created when it is called. i also downloaded the code from this site, but it not works too. i want to know why it not creates Log.txt file in FileLogs directory? maybe somewhere must be the EndInvoke method?
i'm on windows xp sp3.
sorry for bad english and thanks for answer.

samuraisxmali · November 10th, 2011, 06:21 AM

Quote:

Originally Posted by ChristianNagel

Did you verify if any of the file system watcher event handler is invoked while you run the application? If it is not try changing the Filter property of the FileSystemWatcher to "*.txt" instead of the filename.

i tried it and changed filter but result is same - nothing happens.

i debugged it step by step and none of filesystemwatcher event hendlers are invoked, it gets on initializations

Code:

 this.watcher = new FileSystemWatcher();
            this.watcher.Deleted +=
            new FileSystemEventHandler(this.OnDelete);
            this.watcher.Renamed +=
            new RenamedEventHandler(this.OnRenamed);
            this.watcher.Changed +=
            new FileSystemEventHandler(this.OnChanged);
            this.watcher.Created +=
            new FileSystemEventHandler(this.OnCreate);

but not exactly event handlers. even when i changed the filter. i tried everything i know, but...

samuraisxmali · November 10th, 2011, 06:27 AM

Quote:

Originally Posted by ChristianNagel

Did you verify if any of the file system watcher event handler is invoked while you run the application? If it is not try changing the Filter property of the FileSystemWatcher to "*.txt" instead of the filename.

changed filter but the result is same.
i debugged step by step and none of event handlers are invoking, it gets only initializations such as

Code:

 this.watcher = new FileSystemWatcher();
            this.watcher.Deleted +=
            new FileSystemEventHandler(this.OnDelete);
            this.watcher.Renamed +=
            new RenamedEventHandler(this.OnRenamed);
            this.watcher.Changed +=
            new FileSystemEventHandler(this.OnChanged);
            this.watcher.Created +=
            new FileSystemEventHandler(this.OnCreate);

i don't know what to think. i tried everything i knew. can you test it to see whats wrong? thanks.

ChristianNagel · November 13th, 2011, 01:19 PM

Quote:

Originally Posted by samuraisxmali

changed filter but the result is same.
i debugged step by step and none of event handlers are invoking, it gets only initializations such as

Code:

 this.watcher = new FileSystemWatcher();
            this.watcher.Deleted +=
            new FileSystemEventHandler(this.OnDelete);
            this.watcher.Renamed +=
            new RenamedEventHandler(this.OnRenamed);
            this.watcher.Changed +=
            new FileSystemEventHandler(this.OnChanged);
            this.watcher.Created +=
            new FileSystemEventHandler(this.OnCreate);

i don't know what to think. i tried everything i knew. can you test it to see whats wrong? thanks.

I've already copied the code you posted, just changed the filter to *.txt, and everything is working. Of course only if you create a new file in the directory that is referenced by the filter, if you change, rename, and delete the file.

dampyr · December 16th, 2011, 07:45 AM

For me everything works fine too,with initial filter code:

Code:

Watcher.Filter=Path.GetFileName(textBox1.Text)