XL2000: Macro Code to Check Whether a File Is Already Open (213383)

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Sample Macro Code

If a given file is not already open, the following macro also opens it. If the file is not in the location you specified, you receive the following error message: To create a Visual Basic procedure to see if Book2.xls in drive C is already open, follow these steps:

1. Start Microsoft Excel, and then press ALT+F11 to open Visual Basic for Applications.
2. In Visual Basic, click Module on the Insert menu.
3. Type the following code in the module sheet:

   Sub TestFileOpened()
   
       ' Test to see if the file is open.
       If IsFileOpen("c:\Book2.xls") Then
           ' Display a message stating the file in use.
           MsgBox "File already in use!"
           '
           ' Add code here to handle case where file is open by another
           ' user.
           '
       Else
           ' Display a message stating the file is not in use.
           MsgBox "File not in use!"
           ' Open the file in Microsoft Excel.
           Workbooks.Open "c:\Book2.xls"
           '
           ' Add code here to handle case where file is NOT open by another
           ' user.
           '
       End If
   
   End Sub
   
   ' This function checks to see if a file is open or not. If the file is
   ' already open, it returns True. If the file is not open, it returns
   ' False. Otherwise, a run-time error occurs because there is
   ' some other problem accessing the file.
   
   Function IsFileOpen(filename As String)
       Dim filenum As Integer, errnum As Integer
   
       On Error Resume Next   ' Turn error checking off.
       filenum = FreeFile()   ' Get a free file number.
       ' Attempt to open the file and lock it.
       Open filename For Input Lock Read As #filenum
       Close filenum          ' Close the file.
       errnum = Err           ' Save the error number that occurred.
       On Error GoTo 0        ' Turn error checking back on.
   
       ' Check to see which error occurred.
       Select Case errnum
   
           ' No error occurred.
           ' File is NOT already open by another user.
           Case 0
            IsFileOpen = False
   
           ' Error number for "Permission Denied."
           ' File is already opened by another user.
           Case 70
               IsFileOpen = True
   
           ' Another error occurred.
           Case Else
               Error errnum
       End Select
   
   End Function