Among the various
CSIDL values you can pass to functions like
CSIDL_DESKTOPDIRECTORY. What’s the difference between them?
CSIDL_DESKTOP is the virtual folder that represents the desktop. The contents of this virtual folder is what gets displayed on top of your wallpaper.
CSIDL_DESKTOP virtual folder is populated from various locations, some of them virtual, and some of them physical. The
CSIDL_DESKTOPDIRECTORY special folder is a physical folder that contains the files that you think of as on your desktop. These are the files that you’ve saved to your desktop, files that you’ve dragged to your desktop, that sort of thing. Some files on the desktop come from
CSIDL_COMMON_DESKTOPDIRECTORY, which is the shared desktop. Files in the shared desktop directory are visible to all users.
What does this mean for you, the programmer? (Well, assuming you are still using
CSIDL values and haven’t switched over to the new
Programs shouldn’t care about
CSIDL_DESKTOPDIRECTORY; they should just operate on
CSIDL_DESKTOP, because that’s what the user sees. If you want to generate an
ITEMIDLIST for a file on the desktop, use the
CSIDL_DESKTOP folder. The physical folder behind the desktop can change (for example, due to roaming user profiles), but the logical location on the desktop remains fixed. If you had generated the
ITEMIDLIST based on
CSIDL_DESKTOPDIRECTORY, then the experience for your users will be much more annoying: They will get file not found errors if the user profile roams to another machine (since the directory has changed). If they perform a Save As operation, the default save location will be some deep file system path instead of just being the desktop.
CSIDL_DESKTOPDIRECTORY is the plumbing behind the scenes. Don’t show it to the user; it’s ugly.