Do not allow access to files being processed 1

[mmetze]

What is the best way to check to see if a file is being accessed by another process? Specifically, if the file is being written, I want to restrict access in a For Each loop when using the FileSystemObject in the Scripting library. For example, I am looking for the code required in the 'FileIsLocked' function in the sample code below...

For Each objFile in objFolder
If Not FileIsLocked(objFile) Then
ProcessFile(objFile)
End If
Next objFile

 

[JustinEzequiel]

this might help you, might not...

Option Explicit

Sub main()
Dim oFile As File
Dim oFSO As FileSystemObject
Dim oFolder As Folder
Dim oStream As TextStream

Set oFSO = New FileSystemObject
Set oFolder = oFSO.GetFolder("C:\&quot
Set oStream = oFSO.OpenTextFile("C:\TinyInvaders.exe", ForAppending)

Set oFSO = Nothing

For Each oFile In oFolder.Files
If FileIsLocked(oFile) Then
MsgBox oFile.Name & " is locked"
Else
Debug.Print oFile.Name & " is not locked"
End If
DoEvents
Next oFile

Set oFile = Nothing
Set oFolder = Nothing

oStream.Close
Set oStream = Nothing
End Sub

Private Function FileIsLocked(ByVal oFile As File) As Boolean
Dim oStream As TextStream

On Error GoTo ERRORHANDLER

Set oStream = oFile.OpenAsTextStream(ForAppending)
On Error GoTo 0

Set oFile = Nothing

oStream.Close
Set oStream = Nothing
FileIsLocked = False
Exit Function

ERRORHANDLER:
Debug.Print ">>>>", Err.Description, oFile.Name
FileIsLocked = True
Set oFile = Nothing
Set oStream = Nothing
End Function

 

[mmetze]

This seems to work well!!! I just have a few questions...

1- The "On Error GoTo 0" stmt is meant to re-execute the entire function upon a failure in closing the textstream object and destroying the fso objects? I'm not trying to be a jerk by asking this, I just want to make sure I'm not missing something.

2- I assume that opening the file as a textstream is more efficient than opening as a random access file using the 'open' method? Any drawbacks in this situation?

3- In testing this, I opened the desired file in WordPad and then stepped through the code without an error being raised. However, when I opened the file with MS-Word, an error was raised. Could it be that Word locks a file when opening, but WordPad does not?


Again, much thanks for the code! I really appreciate the help.

Mark

 

[JustinEzequiel]

I put the 'on error goto 0' statement where it was as i only wanted to catch the error when trying to open the file and not all possible errors in the code

I used open as text stream because you were using the filesystemobject and had assumed that you were too

i myself prefer the regular open statement as I can then explicitly open a file locked for reading, writing or both if I wanted to