Quote Originally Posted by .paul. View Post
The problem with the right click menu is that it runs a program once for every selected file.
I want it to amalgamate all of the selected file names, then… run a program once for the group of selected files, instead of individually one by one.
This isn't true. A shell extension receives every selected file at once. Your DLL is called once per right click with all selected files; it's not like adding an association in the registry.