VBA functions cannot be created using XlsIO but they can be used in templates.This means that you would have to define the functions in VBA using MS Excel and cannot do it during runtime using XlsIO. For example, you can have a spreadsheet that can have macros in it and then use XlsIO to open these spreadsheets as a template and make modifications to the spreadsheet. When this modified spreadsheet is resaved using XlsIO the macro is retained.

XlsIO also provides support for disabling macros in the template workbook as follows. This will just ignore the macros in the template, and work normally as if there were no macros in the template.