file already open in a network drive

[wengang]

one more question..

If several computers are all using copies of an application that shares data held in text files on a common network drive (F , then is there a command that will prevent the program from editing the text file when it is already being edited by another PC file (to avoid the "FILE ALREADY OPEN" error)?


I appreciate any helpful code or suggestions on this. THanks

[KWell]

Yes the command exist. It use and API call.
Before Open the file, test it with the IsFileAlreadyOpen function

Private Declare Function lOpen Lib "kernel32" Alias "_lopen" (ByVal lpPathName As String, ByVal iReadWrite As Long) As Long
Private Declare Function lClose Lib "kernel32" Alias "_lclose" (ByVal hFile As Long) As Long


Function IsFileAlreadyOpen(FileName As String) As Boolean
 Dim hFile As Long
 Dim lastErr As Long

 ' Initialize file handle and error variable.
 hFile = -1
 lastErr = 0

 ' Open for for read and exclusive sharing.
 hFile = lOpen(FileName, &H10)

 ' If we couldn't open the file, get the last error.
 If hFile = -1 Then
    lastErr = Err.LastDllError
    Else
    ' Make sure we close the file on success.
    lClose (hFile)
 End If

 ' Check for sharing violation error.
 If (hFile = -1) And (lastErr = 32) Then
    IsFileAlreadyOpen = True
    Else
    IsFileAlreadyOpen = False
 End If
End Function

[michelle]

Hello wengang,

I allways trying to get my source as simple as possible.
When the next source is not working correctly, please tell me.

Idee: when a file is used, it is not possible to rename it to his own name!


Private Sub Form_Load()
Dim SourceFile As String

SourceFile = "R:\YourFile.XXX"

On Error GoTo FileError
Name SourceFile As SourceFile 'Rename file.
GoTo FileEnd

FileError:
MsgBox "File Used by other application"

FileEnd:
On Error GoTo 0
End Sub


Nice regards,

Michelle.

[Edited by michelle on 07-14-2000 at 02:55 AM]