• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 4527
  • Last Modified:

Wait until file is copied

I need to copy the file and then do something with it.

I am using
File.Copy(Source, Destiination)

If I strat doing something with the file while it is still in the process of being copied I am getting the exception that Access to the file denied.
Does  somebody have a solution how to make sure that the file has been successfully copied and Copying process is finished?

I was trying to check if the file size of the Destination is equal to the size of Source

Dim fi As FileInfo
Dim lLengthOfOld As Long

            'get the length of the file
            fi = New FileInfo(Source)
            lLengthOfOld = fi.Length

            File.Copy(Source, Destination)
                    fi = New FileInfo(Destination)
                    'wait until copied
                    Do While Not fi.Length = lLengthOfOld
                       fi = New FileInfo(Destination)
                    GoTo Label1
                End Try

But sometimes I still get the message that Access denied.
If I run code in Debug mode, execute 1 line at a time, everything works OK
  • 4
  • 2
  • 2
  • +1
2 Solutions
use sleep


depending on how big the file is

seconds of waiting
iboutchkineAuthor Commented:
I have already tried with sleep. It is working, but the problem is that it always takes different time to copy the file. It depends on the type of PC and how PC is busy with other processes. That is why it is not an option. The bottom line - I want to start synchronous process of copying a file and continue only after the copy is done. So far I cannot catch the end of the process. Even if I manage to compare bits written (like in the sample above) it does not mean that the file is closed.
so do a Do while statement

While you get the error of access denied
The 14th Annual Expert Award Winners

The results are in! Meet the top members of our 2017 Expert Awards. Congratulations to all who qualified!

Perhaps this problem goes away if you use an alternative to file.copy
Try copying the file under program control, by opeining it as a binary input file and copying it to an output file one buffer at a time.  It might take a little longer that way but not very much longer because the bottleneck is still really the disk speed not the extra CPU cycles needed to runb your code.  The real difference is that you will be in control of the process and will know exactly when it has finished.

I can give you sample code for this if you need it.

iboutchkineAuthor Commented:
After copying the file I start external program which generates an error - Access denied. My program runs on the background (without user presence). That is why I cannot afford to have messages to appear on my screen

Can you please give me a code


This will copy a file very fast

I think it is similar to what ADSb suggested

                  BinaryReader br = new BinaryReader(new FileStream(@"C:\temp\test.txt",FileMode.Open));
                  BinaryWriter bw = new BinaryWriter(new FileStream(@"C:\test.txt",FileMode.Create));

The only down side to the code provided is that your file must be less than 2.1 Gig in size, which woulnd't work if you are creating a back up program of some sort.

iboutchkineAuthor Commented:
Thank you _TAD_ I will try and get back to you.
iboutchkineAuthor Commented:
Thank you _TAD_ and AdsB. I got it to work. Her eis the code for whoever is interested

 Dim i As Integer
        Dim sFile As String
        Dim arrFiles() As String
        Dim posSep As Integer
        Dim br As BinaryReader
        Dim bw As BinaryWriter

        arrFiles = GetFiles(sDir) 'from MailBox directory

        For i = 0 To arrFiles.GetUpperBound(0)
            posSep = arrFiles(i).LastIndexOf("\")
            ' Get the file name from the full path
            sFile = arrFiles(i).Substring((posSep + 1), arrFiles(i).Length - (posSep + 1))

            If sFile.Substring(0, 3) = "ib_" Then
                br = New BinaryReader(New FileStream(sDir & sFile, FileMode.Open))
                bw = New BinaryWriter(New FileStream(OUT & sFile, FileMode.Create))
            End If
        Next i
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

Featured Post

Free Tool: Port Scanner

Check which ports are open to the outside world. Helps make sure that your firewall rules are working as intended.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

  • 4
  • 2
  • 2
  • +1
Tackle projects and never again get stuck behind a technical roadblock.
Join Now