Hello,
http://libxlsxwriter.github.io/
This week end I found this library to create XLSX files.
I think it is awesome and I created an harbour (incomplete) wrapper, you can found it here: http://aperricone.altervista.org/extras/libxlsxwriter.zip
I put a compiled version of the library made with Visual Studo 2017. To compile the library is necessary use CMake.
I think it could be great use it to create the excel files from TReport and XBrowse.
Regards,
Antonino