How to tell if a file is currently being written to...

[=?Utf-8?B?Um9nZWxpbw==?=]

hey, got a method here (that I took from somewhere) that gets a list of all
the files in a folder.,

/// <summary>
/// Method that gets all the files in a directory and returns an
arraylist of all the files.
/// </summary>
/// <param name="di">Direc tory Info Object</param>
/// <param name="searchPat tern">Search Pattern (*.pdf)</param>
/// <param name="MyFiles"> referenced array list</param>
private void GetFiles(Direct oryInfo di, string searchPattern, ref
ArrayList MyFiles)
{
foreach (FileInfo fi in di.GetFiles(sea rchPattern))
{
MyFiles.Add(fi. FullName);
}
// comment out the following to not Search in subdirctories
foreach (DirectoryInfo d in di.GetDirectori es())
{
GetFiles(d, searchPattern, ref MyFiles);
}

}



the problem is sometimes people are going to be pasting massive ifles in
this folder., like 100+ MB of size. and as you know it will put the file
there, but it wont be done yet.

what kind of "if" statement do I need that checks the file's status that its
not currently being written to?

thanks,

[Jeroen Mostert]

Re: How to tell if a file is currently being written to...

Rogelio wrote:

what kind of "if" statement do I need that checks the file's status that its
not currently being written to?
>

Unfortunately, there's no foolproof way of determining when a process is
"done" writing to a file. The best you can hope for is that the process
keeps open a write lock while it's writing to the file. Even then it mustn't
write in chunks (opening the file, appending some data, then closing it again).

If it does keep open a write lock, all you have to do is try to open the
file for writing with a lock of your own (new FileStream(path ,
FileMode.Open, FileAccess.Writ e, FileShare.None) ). If this fails, the file
is most likely still in use.

Another heuristic is to only process files whose last modified time
(FileInfo.LastW riteTime) is past some specified threshold, so you're
reasonably sure no more writes will occur.

--
J.

[=?Utf-8?B?Um9nZWxpbw==?=]

Re: How to tell if a file is currently being written to...

ok. heres my solution....


/// <summary>
/// Method that gets all the files in a directory and returns an
arraylist of all the files.
/// </summary>
/// <param name="di">Direc tory Info Object</param>
/// <param name="searchPat tern">Search Pattern (*.pdf)</param>
/// <param name="MyFiles"> referenced array list</param>
private void GetFiles(Direct oryInfo di, string searchPattern, ref
ArrayList MyFiles)
{
foreach (FileInfo fi in di.GetFiles(sea rchPattern))
{
//check if the last write time of the file was not 20
seconds ago or sooner.
//this prevents a file currently being written to to be
added to the list of files.
if (fi.LastWriteTi me < DateTime.Now.Ad dSeconds(-20))
{
MyFiles.Add(fi. FullName);
}
}
// Search in subdirctories
foreach (DirectoryInfo d in di.GetDirectori es())
{
GetFiles(d, searchPattern, ref MyFiles);
}

}

"Jeroen Mostert" wrote:

Rogelio wrote:

what kind of "if" statement do I need that checks the file's status that its
not currently being written to?

Unfortunately, there's no foolproof way of determining when a process is
"done" writing to a file. The best you can hope for is that the process
keeps open a write lock while it's writing to the file. Even then it mustn't
write in chunks (opening the file, appending some data, then closing it again).
>
If it does keep open a write lock, all you have to do is try to open the
file for writing with a lock of your own (new FileStream(path ,
FileMode.Open, FileAccess.Writ e, FileShare.None) ). If this fails, the file
is most likely still in use.
>
Another heuristic is to only process files whose last modified time
(FileInfo.LastW riteTime) is past some specified threshold, so you're
reasonably sure no more writes will occur.
>
--
J.
>

[Pavel Minaev]

Re: How to tell if a file is currently being written to...

On Aug 15, 9:17 pm, Rogelio <Roge...@discus sions.microsoft .comwrote:

ok. heres my solution....
>
        /// <summary>
        /// Method that gets all the files in a directory and returns an
arraylist of all the files.
        /// </summary>
        /// <param name="di">Direc tory Info Object</param>
        /// <param name="searchPat tern">Search Pattern (*.pdf)</param>
        /// <param name="MyFiles"> referenced array list</param>
        private void GetFiles(Direct oryInfo di, string searchPattern, ref
ArrayList MyFiles)
        {
            foreach (FileInfo fi in di.GetFiles(sea rchPattern))
            {
                //check if the last write time of the file was not 20
seconds ago or sooner.
                //this prevents a file currently being written to to be
added to the list of files.
                if (fi.LastWriteTi me < DateTime.Now.Ad dSeconds(-20))
                {
                    MyFiles.Add(fi. FullName);
                }
            }
            // Search in subdirctories
            foreach (DirectoryInfo d in di.GetDirectori es())
            {
                GetFiles(d, searchPattern, ref MyFiles);
            }
>
        }

If you really want to follow the route of keeping track of the time of
the last write, then why not use FileSystemWatch er class with
NotifyFilters.L astWrite? It will be much more efficient.