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Posted 8 Jan 2004


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File Processor

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8 Jan 20041 min read
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.

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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.

Comments and Discussions

GeneralRe: Here's a solution... Pin
sides_dale10-Oct-08 20:01
Membersides_dale10-Oct-08 20:01 
QuestionHow to avoid polling while file is open Pin
Eron Wright29-Jan-04 13:18
MemberEron Wright29-Jan-04 13:18 
AnswerRe: How to avoid polling while file is open Pin
cosmicb18-Feb-04 1:54
Membercosmicb18-Feb-04 1:54 
GeneralRe: How to avoid polling while file is open Pin
Eron Wright18-Feb-04 4:56
MemberEron Wright18-Feb-04 4:56 
GeneralRe: How to avoid polling while file is open Pin
cosmicb27-Aug-04 7:03
Membercosmicb27-Aug-04 7:03 
GeneralRe: How to avoid polling while file is open Pin
Joerg Brunke17-Sep-04 9:05
MemberJoerg Brunke17-Sep-04 9:05 
GeneralRe: How to avoid polling while file is open Pin
cosmicb21-Sep-04 2:37
Membercosmicb21-Sep-04 2:37 
QuestionHow do I configure application Pin
extremeg9-Jan-04 6:09
Memberextremeg9-Jan-04 6:09 
Monitoring when a file copy operation via a C# application is cool - well done. But how do I configure the application to do this. Please give an example and a concise description.

...the mind is not a vessel to be filled but a fire to ignited
AnswerRe: How do I configure application Pin
cosmicb12-Jan-04 2:07
Membercosmicb12-Jan-04 2:07 
GeneralInstead of counting I/O... Pin
Daniel Turini9-Jan-04 0:56
MemberDaniel Turini9-Jan-04 0:56 
GeneralRe: Instead of counting I/O... Pin
cosmicb12-Jan-04 2:36
Membercosmicb12-Jan-04 2:36 
GeneralRe: Instead of counting I/O... Pin
Member 97736220-Jun-04 12:39
MemberMember 97736220-Jun-04 12:39 
GeneralRe: Instead of counting I/O... Pin
cosmicb27-Aug-04 7:43
Membercosmicb27-Aug-04 7:43 

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