Quick C# Question

  • Thread starter Thread starter McFly Racing
  • Start date Start date
M

McFly Racing

I have a file being copied to my server from another server on the network.
My program needs to work with this file when it is received on my server.
The problem I have is that when I go to process the file it may still be
being written to the disk and thus I cannot get a valid handle on it to
perform the necessary operations I need to do.



The code I inherited uses a sleep on the thread that the code is running in.
I am looking for a more elegant solution that does not put the thread to
sleep for some static amount of time. Any suggestions would be greatly
appreciated. Thank you.
 
Maybe, you can use File's lastmodified/created date to determine whether the
file is completely written on it or not

Alternatively, you could use FileSystemWatcher class which gives notification
when a new file is written/deleted etc

Does this help ?

Kalpesh
 
Hi McFly,

Maybe FileSystemWatcher will help you, although I'm not familiar with it
nor know if it will simplify trying to read the file while it is being
written.
 
I am using a FileSystemWatcher and it raises the events before I can get a
handle to the file. I think this is either because the file is still being
written or the disk is doing a lasy write. Thank you for your input.
 
I am using a FileSystemWatcher and it raises the events before I can get a
handle to the file. I think this is either because the file is still being
written or the disk is doing a lasy write. Thank you for your input.
 
This is the code I wrote for that. See if it is of any use for you.

/// <summary>
/// Makes sure that the file is fully saved by trying to open it for
ReadWrite.
/// Generates exception if fails to do this within given period of
time.
/// </summary>
/// <param name="fi">FileInfo of the file to watch</param>
/// <param name="toSeconds">timeout in seconds</param>
/// <exception cref="System.Exception">Timeout: file is locked by
the writing process for more than specified time</exception>
static public void WaitForFullySaved (FileInfo fi, int toSeconds)
{
int timeout;
FileStream fs;

timeout = toSeconds * 1000;
while (timeout > 0)
try
{
fs = fi.Open (FileMode.Open, FileAccess.ReadWrite);
fs.Close ();
break;
}
catch (IOException)
{
System.Threading.Thread.Sleep (500);
timeout -= 500;
}
if (timeout <= 0)
throw (new Exception (String.Format (
"File {1} is locked by the writing process for more than
{2} seconds",
fi.Name, toSeconds)));
}

Eliyahu
 
This is what I was looking for. Thank you.

Eliyahu Goldin said:
This is the code I wrote for that. See if it is of any use for you.

/// <summary>
/// Makes sure that the file is fully saved by trying to open it for
ReadWrite.
/// Generates exception if fails to do this within given period of
time.
/// </summary>
/// <param name="fi">FileInfo of the file to watch</param>
/// <param name="toSeconds">timeout in seconds</param>
/// <exception cref="System.Exception">Timeout: file is locked by
the writing process for more than specified time</exception>
static public void WaitForFullySaved (FileInfo fi, int toSeconds)
{
int timeout;
FileStream fs;

timeout = toSeconds * 1000;
while (timeout > 0)
try
{
fs = fi.Open (FileMode.Open, FileAccess.ReadWrite);
fs.Close ();
break;
}
catch (IOException)
{
System.Threading.Thread.Sleep (500);
timeout -= 500;
}
if (timeout <= 0)
throw (new Exception (String.Format (
"File {1} is locked by the writing process for more than
{2} seconds",
fi.Name, toSeconds)));
}

Eliyahu
Click to expand...
 
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