When an application data file is dropped on a printer object, the application can receive a DM_PRINTOBJECT message if the application is running currently.
One DM_PRINTOBJECT parameter gives a DRAGITEM structure that describes the object that was dropped. The other parameter gives a PRINTDEST structure that contains all the parameters required to call DevPostDeviceModes and DevOpenDC.
The PD_JOB_PROPERTY flag indicates to the application that the user has requested a job properties dialog before printing. If this flag is not set, the application must not display the job properties dialog; it must use the job properties passed in the PRINTDEST structure.
The rest of the printing process follows the procedure described in Submitting a Queued Presentation Manager Print Job.