Difference between CreateObject(“Excel.Application”) .Workbooks.Open and just Workbooks.Open

Question

I am currently using Workbooks.Open to process a large number of files contained in a directory. But opening and closing these files make the files appear in the ta

Answer 1

Workbooks.Open uses the current MS Excel instance and CreateObject(“Excel.Application”) creates a new MS Excel instance. You can read up on CreateObject here.

Simply issuing a Workbooks.Open after creating a new instance will not ensure that the workbooks open in the new instance. You will have to bind with it. For example

Dim oXLApp As Object, wb As Object

Set oXLApp = CreateObject("Excel.Application")

'~~> Hide Excel
oXLApp.Visible = False

'~~> Open files
Set wb = oXLApp.Workbooks.Open("C:\Sample.xls")

Regarding your other question

Also, should I just use one instance of Excel created using CreateObject to open all Workbooks or do I need to create one instance for each workbook I have to process

You don't need several instances. You can work with one instance. For example

Dim oXLApp As Object, wb As Object

Set oXLApp = CreateObject("Excel.Application")

'~~> Hide Excel
oXLApp.Visible = False

'~~> Open files
Set wb = oXLApp.Workbooks.Open("C:\Sample1.xls")

'
'~~> Do some Stuff
'

wb.Close (False)

'~~> Open files
Set wb = oXLApp.Workbooks.Open("C:\Sample2.xls")
'
'~~> Do some Stuff
'

wb.Close (False)

'
'~~> And So on
'