A DLL just needs to provide the xlAutoOpen function to become a valid XLL Add-In. It’s quite easy to say ‘Hello Excel!’ with Delphi that way. The xlAuto family is a set of interface functions Excel uses for XLL interaction. Continue reading →

Excel enables a DLL to call back into Excel. Your Delphi Add-In will need to use this feature provided with the Excel4v and Excel12v callback functions. We import the Excel4v function and implement the Excel12v function. Hence we’ve got the objects to write Delphi XLL Add-Ins. Continue reading →