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Posted 8 Jan 2004

File Processor

, 8 Jan 2004
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An article on processing a File using the FileSystemWatcher class


The purpose of this article is to address the lack of information that is available from the FileSystemWatcher utility class.


The problem with the FileSystemWatcher class is we don't know when exactly has the file copy completed in order to process the file?

Using the code

The Monitor class wraps the FileSystemWatcher's functionality. The FileObject class encapsulates a newly copied file's general information as well as providing a method call that returns an output stream which can be manipulated.

// Monitor Class
// This is the implementation of a FileSystemWatcher class.
// The static ConfigurationInfo class is a technique I use to 
// make global information available to an application.
// The Notifyfilters are important so that the required IO event is fired.
private void SystemWatch()
    FileSystemWatcher watcher = new FileSystemWatcher();
    watcher.Path = ConfigurationInfo.ModulePath+
    watcher.NotifyFilter = NotifyFilters.LastWrite  | 
       NotifyFilters.FileName ; 
    watcher.Filter = "*.*";
    watcher.Created += new FileSystemEventHandler(OnChanged);
    watcher.Changed += new FileSystemEventHandler(OnChanged);
    watcher.EnableRaisingEvents = true;

The next tricky bit is knowing when to start processing the file i.e. when has the file copy completed.

Someone else might come up with a better solution but in the RAD environment that I program in development speed and stability are very important. The trick is to user a SystemTimer which has a fairly low resource impact and increment the timer interval every time an IO event is fired. Obviously once the file copy has completed the interval will not be incremented and the timer will timeout.

// The FileObject when constructed creates and starts the LogTimer class.
// LogTimer wraps a System timer.
private System.Timers.Timer LogTimer = new System.Timers.Timer();
// LogTimer constructor. The AutoReset set to false 
// means that the timer will only fire once.
public LogFileTimer(int tTime, string Name)
    PollTime = tTime;
    fileName = Name;
    LogTimer.Elapsed += new ElapsedEventHandler(Timeup);
    LogTimer.Interval = PollTime;
    LogTimer.Enabled = true;
    LogTimer.AutoReset = false; 

Points of Interest

The big problem this solution solves is that large files copied into a monitored directory can only be processed once the copy or FTP has completed. I think the solution is neat but probably can be scaled down even further. I used these objects to convert a very large FTP'd flat file into XML.


This is my first article so go easy.


This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here


About the Author

Web Developer
South Africa South Africa
I studied IT in 1987 and have been working ever since in on projects that range from coding animation in pascal and assembler to writing secure internet banking web sites.

I live in South Africa and I think because of it's size we're required to do more for less which makes highly skilled in a wide range of skills and technologies.

I have the bonus of living in a coastal town so time away from computers is spent around the sea and in sunshine and nature.

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Comments and Discussions

GeneralSemaphore File Pin
cosmicb6-Sep-07 14:42
membercosmicb6-Sep-07 14:42 
QuestionLower Case Full Path and Name Pin
Nizhum27-May-07 2:40
memberNizhum27-May-07 2:40 
QuestionCan you please tell how to test this program? Pin
Bharat Gadhia11-Aug-06 12:37
memberBharat Gadhia11-Aug-06 12:37 
AnswerRe: Can you please tell how to test this program? Pin
cosmicb6-Sep-07 14:36
membercosmicb6-Sep-07 14:36 
QuestionCan you please tell how to test this program? Pin
Bharat Gadhia11-Aug-06 12:36
memberBharat Gadhia11-Aug-06 12:36 
GeneralCorrect Method For New Files Pin
redtoad22-Jul-06 15:56
memberredtoad22-Jul-06 15:56 
GeneralAnother approach without using timer or exception Pin
Chitrsen18-Jul-06 1:52
memberChitrsen18-Jul-06 1:52 
QuestionRe: Another approach without using timer or exception Pin
sides_dale14-Apr-07 16:48
membersides_dale14-Apr-07 16:48 
AnswerRe: Another approach without using timer or exception Pin
krishpuma25-May-07 1:00
memberkrishpuma25-May-07 1:00 
QuestionHow to implement via windows services Pin
vittoriod18-Oct-05 5:14
membervittoriod18-Oct-05 5:14 
GeneralBetter lightweight approach with FileShare exclusive open Pin
banditking10-Aug-05 5:34
memberbanditking10-Aug-05 5:34 
GeneralRe: Better lightweight approach with FileShare exclusive open Pin
Richard Roe29-Jan-06 23:44
memberRichard Roe29-Jan-06 23:44 
GeneralWorks Great Pin
Nikhils3316-May-05 5:44
memberNikhils3316-May-05 5:44 
GeneralProgram bombs for large files Pin
Simeon_Shapiro7-May-05 23:44
memberSimeon_Shapiro7-May-05 23:44 
GeneralRe: Program bombs for large files Pin
sdelbos30-May-05 6:01
membersdelbos30-May-05 6:01 
GeneralRe: Program bombs for large files Pin
Richard Roe29-Jan-06 23:46
memberRichard Roe29-Jan-06 23:46 
GeneralRe: Program bombs for large files Pin
Richard Roe29-Jan-06 23:49
memberRichard Roe29-Jan-06 23:49 
GeneralRe: Program bombs for large files Pin
The Prisoner18-Sep-06 1:21
memberThe Prisoner18-Sep-06 1:21 
Generalremove when event fires Pin
Tyler Jensen12-Apr-05 6:26
memberTyler Jensen12-Apr-05 6:26 
GeneralRe: remove when event fires Pin
cosmicb14-Apr-05 1:00
membercosmicb14-Apr-05 1:00 
GeneralWhy both onChanged and onCreated Pin
jabailo21-Mar-05 8:08
memberjabailo21-Mar-05 8:08 
GeneralRe: Why both onChanged and onCreated Pin
cosmicb14-Apr-05 0:55
membercosmicb14-Apr-05 0:55 
Generaldoesn`t detect Copy Pin
Adnan Siddiqi27-Oct-04 22:36
memberAdnan Siddiqi27-Oct-04 22:36 (saving a file ) Pin
Anonymous12-May-04 6:42
memberAnonymous12-May-04 6:42 
GeneralHere's a solution... Pin
DCuca23-Mar-04 15:41
memberDCuca23-Mar-04 15:41 

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