Because the OnCustomCommand event only takes numeric codes as input parameters, you cannot directly pass strings to the service. For example, if you wanted to reconfigure a directory name for a service, you could not just send the directory name over. Instead, it would be necessary to place the information to be passed to the service in a file in some known location on disk. Then a custom command for the service could instruct it to look at the standard file location and read the information in the file. What the service did with the contents of the file would, of course, be customized for the service.