Here is a simple Delphi function that retrieves the location of Windows special folders, such as desktop, start menu, program files, fonts, AppData, etc. The function is useful when attempting to search within the special folders or to create a shortcut link (e.g., a link on the Windows desktop). For additional Delphi code for the Windows operating system, see Useful Delphi Code for the Windows Operating System.

function WindowsSpecialFolderLocation(FolderID: Integer): String;
var
   PIDL: PItemIDList; //uses ShlObj unit
   InFolder: Array[0..MAX_PATH-1] of Char;
begin
     WindowsSpecialFolderLocation := '';

     try
        SHGetSpecialFolderLocation(0, FolderID, PIDL);
        If Assigned(PIDL) then
           begin
                If SHGetPathFromIDList(PIDL, InFolder) = True then WindowsSpecialFolderLocation := String(InFolder);
           end;
     except
           WindowsSpecialFolderLocation := '';
     end;
end;

The procedure below uses the function shown above to get the location of a few Windows special folders.

procedure TForm1.Button1(Sender: TObject);
var
   Desktop, CommonDesktop, MyDocuments, CommonDocuments, ProgramsFiles, StartMenu, CommonStartMenu, Programs, CommonPrograms, Startup, Recent, Favorites, Fonts, AppData, LocalAppData, CommonAppData: String;
begin
     //variables should always be properly initialized
     Desktop := '';
     CommonDesktop := '';
     MyDocuments := '';
     CommonDocuments := '';
     ProgramsFiles := '';
     StartMenu := '';
     CommonStartMenu := '';
     Programs := '';
     CommonPrograms := '';
     Startup := '';
     Recent := '';
     Favorites := '';
     Fonts := '';
     AppData := '';
     LocalAppData := '';
     CommonAppData := '';

     //folder IDs are in the ShlObj unit
     Desktop := WindowsSpecialFolderLocation(CSIDL_DESKTOP);
     CommonDesktop := WindowsSpecialFolderLocation(CSIDL_COMMON_DESKTOPDIRECTORY);
     MyDocuments := WindowsSpecialFolderLocation(CSIDL_MYDOCUMENTS);
     CommonDocuments := WindowsSpecialFolderLocation(CSIDL_COMMON_DOCUMENTS);
     ProgramsFiles := WindowsSpecialFolderLocation(CSIDL_PROGRAM_FILES);
     StartMenu := WindowsSpecialFolderLocation(CSIDL_STARTMENU);
     CommonStartMenu := WindowsSpecialFolderLocation(CSIDL_COMMON_STARTMENU);
     Programs := WindowsSpecialFolderLocation(CSIDL_PROGRAMS);
     CommonPrograms := WindowsSpecialFolderLocation(CSIDL_COMMON_PROGRAMS);
     Startup := WindowsSpecialFolderLocation(CSIDL_STARTUP);
     Recent := WindowsSpecialFolderLocation(CSIDL_RECENT);
     Favorites := WindowsSpecialFolderLocation(CSIDL_FAVORITES);
     Fonts := WindowsSpecialFolderLocation(CSIDL_FONTS);
     AppData := WindowsSpecialFolderLocation(CSIDL_APPDATA);
     LocalAppData := WindowsSpecialFolderLocation(CSIDL_LOCAL_APPDATA);
     CommonAppData := WindowsSpecialFolderLocation(CSIDL_COMMON_APPDATA);
end;

Below is a non-exhaustive list of defined constants for special folders. The values for special folders (CSIDL, constant special item ID list) can be found in the ShlObj unit. For additional information, please see the Microsoft CSIDL page.

CSIDL_DESKTOP

CSIDL_INTERNET

CSIDL_PROGRAMS

CSIDL_CONTROLS

CSIDL_PRINTERS

CSIDL_PERSONAL

CSIDL_FAVORITES

CSIDL_STARTUP

CSIDL_RECENT

CSIDL_SENDTO

CSIDL_BITBUCKET

CSIDL_STARTMENU

CSIDL_MYDOCUMENTS

CSIDL_MYMUSIC

CSIDL_MYVIDEO

CSIDL_DESKTOPDIRECTORY

CSIDL_DRIVES

CSIDL_NETWORK

CSIDL_NETHOOD

CSIDL_FONTS

CSIDL_TEMPLATES

CSIDL_COMMON_STARTMENU

CSIDL_COMMON_PROGRAMS

CSIDL_COMMON_STARTUP

CSIDL_COMMON_DESKTOPDIRECTORY

CSIDL_APPDATA

CSIDL_PRINTHOOD

CSIDL_LOCAL_APPDATA

CSIDL_ALTSTARTUP

CSIDL_COMMON_ALTSTARTUP

CSIDL_COMMON_FAVORITES

CSIDL_INTERNET_CACHE

CSIDL_COOKIES

CSIDL_HISTORY

CSIDL_COMMON_APPDATA

CSIDL_WINDOWS

CSIDL_SYSTEM

CSIDL_PROGRAM_FILES

CSIDL_MYPICTURES

CSIDL_PROFILE

CSIDL_SYSTEMX86

CSIDL_PROGRAM_FILESX86

CSIDL_PROGRAM_FILES_COMMON

CSIDL_PROGRAM_FILES_COMMONX86

CSIDL_COMMON_TEMPLATES

CSIDL_COMMON_DOCUMENTS

CSIDL_COMMON_ADMINTOOLS

CSIDL_ADMINTOOLS

CSIDL_CONNECTIONS

CSIDL_COMMON_MUSIC

CSIDL_COMMON_PICTURES

CSIDL_COMMON_VIDEO

CSIDL_RESOURCES

CSIDL_RESOURCES_LOCALIZED

CSIDL_COMMON_OEM_LINKS

CSIDL_CDBURN_AREA

CSIDL_COMPUTERSNEARME

CSIDL_FLAG_CREATE

CSIDL_FLAG_DONT_VERIFY

CSIDL_FLAG_DONT_UNEXPAND

CSIDL_FLAG_NO_ALIAS

CSIDL_FLAG_PER_USER_INIT

CSIDL_FLAG_MASK

CSIDL_PROFILES