Re: Filtering FileSystemWatcher Events By File Size - C# Discussion Boards

Filtering FileSystemWatcher Events By File Size

6-Jan-09 7:56

Your application is going to need some heavy work in it's ability to plan, design, and generate code. Most flowcharts simply don't provide enough information to generate code like you want. Also, your app is (I can't believe I'm saying this) going to have to understand English in order to do this.

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Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008

rich_wenger6-Jan-09 4:03

Re: Filtering FileSystemWatcher Events By File Size

6-Jan-09 4:03

Hi,

I am attempting to create a service to watch particular directories for excessively large files being created. I've created a Created event handler with the following code:

void fileSystemWatcher1_Created(object sender, FileSystemEventArgs e)
{
FileInfo fi = new FileInfo(e.FullPath);
if (fi.Length > 524288000)// 500MB = 524288000
{
smtpMessage.Body = "A file exceeding 500 MB has been created at " + e.FullPath.ToUpper();
Client.Send(smtpMessage);
}
}

I drop files one at a time into the watched directory and I'll get an email alert for the first file but nothing for subsequent files? Any help greatly appreciated.

C. Richard Wenger

System Administrator

#realJSOP6-Jan-09 4:30

Re: Filtering FileSystemWatcher Events By File Size

6-Jan-09 4:30

How are you initializing the watcher?

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rich_wenger6-Jan-09 8:08

Re: Filtering FileSystemWatcher Events By File Size

6-Jan-09 8:08

This is what I have setup:

this.fileSystemWatcher1.Path = directoryPath1;
this.fileSystemWatcher1.IncludeSubdirectories = true;
this.fileSystemWatcher1.Filter = "*.*";
this.fileSystemWatcher1.Created += new FileSystemEventHandler(fileSystemWatcher1_Created);

C. Richard Wenger

System Administrator

#realJSOP6-Jan-09 8:21

Re: Filtering FileSystemWatcher Events By File Size

6-Jan-09 8:21

You haven't set a NotifyFilter, and you haven't turned on EnableRaisingEvents...

rich_wenger6-Jan-09 8:40

Re: Filtering FileSystemWatcher Events By File Size

6-Jan-09 8:40

Sorry, I've got EnableRaisingEvents = true in the OnStart method for the service. I'm not certain how I would code a NotifyFilter since none of them seem to relate to file size?

C. Richard Wenger

System Administrator

Dave Kreskowiak6-Jan-09 9:24

Re: Filtering FileSystemWatcher Events By File Size

6-Jan-09 9:24

There are no file size filters in the FSW. The filter is just there so the FSW knows which events you want to check for.

The FSW polls the filesystem, taking snapshot after snapshot of the monitored directies and their files Created and LastModified times. Then it compares the new snapshot with the old one, generating the required events based on the differences between the two snapshots, subject to the NotifyFilter specification.

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Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008

#realJSOP6-Jan-09 9:29

Re: Filtering FileSystemWatcher Events By File Size

6-Jan-09 9:29

Well, I see a NotifyFilters.Size - isn't that what you want?

At the same time, it might be better to filter on NotifyFilters.LastWrite so that you only have to deal with one event when the file is closed. At that point, you see how big the file is, and act accordingly, but you only do it once per file. Much more efficient.

rich_wenger6-Jan-09 11:19

Re: Filtering FileSystemWatcher Events By File Size

6-Jan-09 11:19

I looking over what you've said and I'm trying to see if there is a way I can leverage this to a useable outcome. As I read it the NotifyFilters.Size reports a CHANGE in file size and I'm not certain how I could use this in my application. The goal is to send email alerts only when files are copied into a directory over a predertimed size limit (if that helps).

C. Richard Wenger

System Administrator

#realJSOP6-Jan-09 23:10

Re: Filtering FileSystemWatcher Events By File Size

6-Jan-09 23:10

Then you want to set the LastWrite filter. That way, when the file is closed, you'll be notified, and you can check the size. If your goal is to determine the size of the file *before* it's written, I don't think that's possible.

Dave Kreskowiak6-Jan-09 7:53

Re: Filtering FileSystemWatcher Events By File Size

6-Jan-09 7:53

rich_wenger wrote:
FileInfo fi = new FileInfo(e.FullPath);
if (fi.Length > 524288000)// 500MB = 524288000

This isn't going to work. When a file is created, it's length is always 0. Only when the application flushes it's writes to the file does the filesize increase, for which there is NO FSW event.

Your code has to keep track of the files that are new, then occasionally check back with those files to get their current sizes, then you can do what's necessary.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008

rich_wenger6-Jan-09 8:10

Re: Filtering FileSystemWatcher Events By File Size

6-Jan-09 8:10

I think I understand what you are saying, I am just not certain why I am getting the first email alert?

C. Richard Wenger

System Administrator

Dave Kreskowiak6-Jan-09 9:19

6-Jan-09 9:19

FSW events don't fire exactly when the actual event occurs. In your case, it appears that the system was doning something else, blocking your application, but still queueing up the Create event. By the time your Create handler got called, the file had attained the require size to trip the email.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008

RegEx

Abdul Rahman Hamidy6-Jan-09 3:51

Abdul Rahman Hamidy

6-Jan-09 3:51

Dear All,
I have problem in defining the correct email address using RegEx.
e.g i have 3 email address as follows
1. ______@yahoo.com
2.abc123@yahoo.com
3. abdul_rahmancs@yahoo.com
now if we just look at mentioned email address only 2 and 3 are correct.
how can i identify the valid email address using regex.

Abdul Rahaman Hamidy
B.Comp.S
Kabul, Afghanistan
Database Developer

Simon P Stevens6-Jan-09 3:58

Simon P Stevens

6-Jan-09 3:58

Validating email addresses kinda of depends how strict you want to be.

There's a good article here that gives some examples and explains their weaknesses and strengths: http://www.regular-expressions.info/email.html[^]

Simon

Wendelius6-Jan-09 3:58

Wendelius

6-Jan-09 3:58

Have you looked at this: http://www.codeproject.com/KB/recipes/EmailRegexValidator.aspx[^]

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Paddy Boyd6-Jan-09 4:09

Paddy Boyd

6-Jan-09 4:09

I don't think that there's anything illegal with the first one either, it's just a little unlikely. Trying to validate email addresses as being real is a different matter.