How open stream or base64 of excel file by Office.Interop.Excel C#
See the question and my original answer on StackOverflowIn any .NET language (VB.NET included) the Open method only takes a string as input. The answer to your link seems quite wrong, I don't see how that could work with a FileStream (or a Stream).
You can use other 3rd party libraries for that, but not Excel itself.