Excel Taking Ages to Unload

[Eugbug]

I am opening an Excel file from VB, saving some data to a sheet and then closing the file. For some reason when I close Excel, it seems to take up to a minute to unload (looking at task manager). If I open a saved XLS file before it closes properly, it doesn't display the contents of the sheet, just a transparent window through which I can see the desktop. Is it the case that I am not closing the workbook, worksheet and application down properly, and some "housekeeping" routine in the background is doing this for me after a timeout period?

This is the code:

 Dim oXL As Object
 Dim oWB As Object
 Dim oSheet As Object

 Private Sub excelopen()

        'Start Excel and get Application object.
        oXL = CreateObject("Excel.Application")

        ' Add a new workbook....
        oWB = oXL.Workbooks.add

        oXL.Visible = True
        oSheet = oWB.sheets(1)


        oXL.UserControl = False

        ' Prevent user editing worksheet
        oXL.interactive = False
        ' Don't display warnings warnings in Excel
        oXL.DisplayAlerts = False
    End Sub

 Private Sub excelwrite(ByVal value_to_write As String, ByVal row As Integer, ByVal column As Integer)
        Try
            oSheet.unprotect()
           ' store some data in cells here
            oSheet.columns.autofit()
            oSheet.protect()
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
 End Sub

 Private Sub excelclose()

        oSheet = Nothing
        Try
         oWB.SaveAs(My.Computer.FileSystem.SpecialDirectories.Desktop & "\test.xls")
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
        oWB.Close(SaveChanges:=False)
        ' Close references and release memory
        oWB = Nothing
        oXL.interactive = True
        oXL.DisplayAlerts = True
        oXL.Quit()
        oXL = Nothing
    End Sub

[dunfiddlin]

There have been reports of difficulties closing Excel several times on this forum but I have to say that I've never experienced any problems. There are potential hol-ups in your closing sub

Private Sub excelclose()
 
        oSheet = Nothing ' if that's here then how does .... 
        Try
         oWB.SaveAs(My.Computer.FileSystem.SpecialDirectories.Desktop & "\test.xls") ' .... this have anything to save?
        Catch ex As Exception
            MsgBox(ex.Message) ' aaargh! Don't tell me it didn't work, enable me to try again until it does!
        End Try
        oWB.Close(SaveChanges:=False) ' so if it failed I've lost everything? Cheers!
' the workbook is automatically closed when the application closes anyway so
        
        oWB = Nothing ' personally I'd do this later
        oXL.interactive = True ' what?
        oXL.DisplayAlerts = True ' huh?
' Why are we setting attributes for an object we're a millisecond away from disposing, especially as we already closed the workbook where any
' alerts would come from?
        oXL.Quit()
        oXL = Nothing 
    End Sub

.

[Eugbug]

Ok, dunfiddlin I take all your points! osheet = nothing coming before owb.SaveAs is from si_the_geek's tutorial here: http://www.vbforums.com/showthread.p...8or-VB5-VBA%29 So blame him
I discovered that this delay is due to the garbage disposal process which results in "non-deterministic finalization". So it seems I have to use a dispose method to remove objects.

[si_the_geek]

Ok, dunfiddlin I take all your points! osheet = nothing coming before owb.SaveAs is from si_the_geek's tutorial here: http://www.vbforums.com/showthread.p...8or-VB5-VBA%29 So blame him

Nice try, but that tutorial is explicitly for other variants of VB rather than VB.Net, so blame yourself.

As for whether or not it would be a good idea to de-reference the sheet at that position in VB.Net, I do not have enough experience with using Excel from VB.Net to be sure how it will act... I wouldn't be surprised if it is fine tho.