[VB.NET] Delete File in process

[James Rose]

Ok gang,

I've got an interesting problem. I have a .net 2.0 app that goes off to a server to get a file and unzip it locally. This process is threaded. It's possible that during the first run through the process the end-user may need to stop the original process and go get a different file.

So, I abort the initial thread and start over. The issue? (Glad you asked) Seems that one or more files (the zip and possibly files from within the zip file, depending on how far along the initial process is) will not delete (File.Delete(path) as these files are in use my another process.

Exact error:

Description: The process cannot access the file 'c:\TestExtract\75872-01-1.ado' because it is being used by another process.

The code that is pulling the file from the zip is here:

--- BEGIN CODE CHUNK --------

If (sFileName <> String.Empty) Then

Dim StreamWriter As FileStream = File.Create(sDirectory & theEntry.Name)

Dim Size As Integer = 2048

Dim data(2048) As Byte

While (True)

Size = stmZipFile.Read(data, 0, data.Length)

If (Size > 0) Then

StreamWriter.Write(data, 0, Size)

Else

Exit While

End If

End While

StreamWriter.Close()

End If

--- END OF CODE CHUNK --------

Ive tried watching for the thread's abort request in that loop, but it never gets it. So I can't close the stream (arg)

I've looked to see if I can get the handle of the process that is using the file so I can kill the process and then the file... but so far no luck. I'm heading home now, but I'll check back in a few hours (it's 5pm est)

Thanks for any ideas.

[bleepjay]

The quickest thing that I would offer would be to have some type of boolean variable that the code chunk continuously checks within it's while(true) loop. such as

While(_cancelZip = false)
   Size = stmZipFile.Read(data, 0, data.Length)
   If (Size > 0) Then
	  StreamWriter.Write(data, 0, Size)
   Else
	  Exit While
   End If
End While

_cancelZip should be a private member variable that can be accessed externally through an Exposed Property.

After this loop, check to see if _cancelZip = true. If it is, you must close this StreamWriter and then delete the file.

Does this make sense?

[magik]

There is a FileSystemWatcher component that you may be able to use. Have you looked into that?

EDIT: Re-read your question and the FileSystemWatcher probably isn't what you're looking for.

Anyway, you are right in looking for the Abort Thread request, but the fact that you aren't getting that means that you are most likely not threading properly. Although bleepjay's solution will probably work, it is clumsy and not the way it should be done with the advent of Threading in .NET. I recommend you look at some of the many threading tutorials online.

Here are a few links I Googled quickly, hope it's useful:

http://msdn.microsoft.com/msdnmag/issues/01/07/vbnet/

http://www.devx.com/getHelpOn/10MinuteSolution/20365

http://www.stardeveloper.com/articles/disp...0404&page=1

http://blogs.msdn.com/dougturn/archive/200...and-vb-net.aspx

Edited August 1, 2007 by magik

[James Rose]

  bleepjay said:

The quickest thing that I would offer would be to have some type of boolean variable that the code chunk continuously checks within it's while(true) loop. such as

While(_cancelZip = false)
   Size = stmZipFile.Read(data, 0, data.Length)
   If (Size > 0) Then
	  StreamWriter.Write(data, 0, Size)
   Else
	  Exit While
   End If
End While

_cancelZip should be a private member variable that can be accessed externally through an Exposed Property.

After this loop, check to see if _cancelZip = true. If it is, you must close this StreamWriter and then delete the file.

Does this make sense?

Hummm... the boolean is an intesting idea. I can set that, wait a moment and then kill the process. I'll give it a try in the morning.

magik,

As for the file system watcher... how would that help? I need to get a specific file at a specific time, not all the files (there are thousands of them!). But maybe you meant something else that I'm not getting.

[magik]

^ Yea, sorry, I didn't read your question fully the first time. I hope my edited post is of more use to you. :)

To clarify: Instead of looking for the Abort Request within your loop, you should have the loop within a Thread Process and then a separate Event Hander that Handles the Thread Abort Request. When that event is fired, it should halt the Thread Process.

Does that make more sense?