I have an .xlsx attachment in an e-mail in Outlook. I want to get summed length of strings in one of the columns using Outlook macro. Is it possible to read attachements data on the fly in Outlook macro or what is the advised approach? Do I need to save the attachment first, then open it as a workbook and work from there?
You can open the file directly if you are using Open XML API, but it is not accessible in VBA.
Otherwise you can use Excel Object Model to read that file:
Set ExcelApp = CreateObject("Excel.Application")
ExcelApp.Visible = false
Set Workbook = ExcelApp.Workbooks.Open("C:\Path\To\Your\File.xlsx")