A File Manager extension sends an FM_GETFILESELLFN message to retrieve information about a selected file from the active File Manager window (either the directory window or the Search Results window). The selected file can have a long filename.
FM_GETFILESELLFN wParam = (WPARAM) index; // index of selected file lParam = (LPARAM) (LPFMS_GETFILESEL) lpfmsgfs; // selection data
The return value is the zero-based index of the selected file that was retrieved.
Only extensions that support long filenames (for example, network-aware extensions) should use this message.
An extension can use the FM_GETSELCOUNT message to get the count of selected files.
FMExtensionProc, FM_GETFILESEL, FM_GETSELCOUNT, FM_GETSELCOUNTLFN