Do excel workbooks require dedicated excel instances?

[Rhidlor]

Quick question, when working with Excel, does each workbook require its own Excel instance, or can multiple workbooks be opened off of the same Excel instance? I tested both ways, on the surface they both seemed to work, just thought I'd ask here to make sure before proceeding any further. Thanks!

Disclaimer: The following is pseudo code

$excel_instance1 = _Excel_Open()
$workbook1 = _Excel_BookOpen($excel_instance1, @ScriptDir & "\book1.xlsx")
$workbook2 = _Excel_BookOpen($excel_instance1, @ScriptDir & "\book2.xlsx")

Or

$excel_instance1 = _Excel_Open()
$workbook1 = _Excel_BookOpen($excel_instance1, @ScriptDir & "\book1.xlsx")
$excel_instance2 = _Excel_Open()
$workbook2 = _Excel_BookOpen($excel_instance2, @ScriptDir & "\book2.xlsx")

 

Edited March 28, 2019 by Rhidlor
added tags

[FrancescoDiMuro]

@Rhidlor

You can use just an instance, since the object you are using is the Application object of Excel, quite the opposite for the Workbook object, which you can have separated files, so in that case they need to be threated in separate variables (as you're already doing) 

Edited March 28, 2019 by FrancescoDiMuro

[water]

Usually a single instance of Excel is enough.
But if a user and your script manipulate workbooks at the same time then it might be sensible to separate them by starting a new Excel instance for your script.
So you can make sure they do not interfere.

[Rhidlor]

Thanks for enlightening me guys. 😁