Hi Adrian,
Thank you for your interest in Syncfusion products.
1) Does the XLSIO component have its own engine?
Yes. XlSIO component have its own engine for writing and reading Excel files.
How does it read Excel files without Excel being present?
Essential XlsIO is a .NET library that can read and write Microsoft Excel files It features a full-fledged object model similar to the Microsoft Office COM libraries. It does not use COM interop and is built from scratch in C#.Hence it can be used without MsExcel installed. However, to view the output file, you will need some viewer.
2)Does the XLSIO component support Excel spreadsheets that have VBA code in them?
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. However, there are no plans to allow manipulating/running Macros through XlsIO API.
Here is a sample that demonstrates macro usage in XlsIO
http://www.syncfusion.com/Support/user/uploads/VBA_b814797b.zip
Please let me know if you have any other questions.
Regards,
G.Yavana