Accessing LocalApplicationData Equivalent in Delphi - delphi

Question

Using Delphi, how do I access the equivalent of .NET's System.Environment.SpecialFolder.LocalApplicationData variable (which works on any version of Windows)? I assumed I could just do:
dir := GetEnvironmentVariable('LOCALAPPDATA');
This works on Vista but XP doesn't seem to set that environment variable by default at least on my test machine.

Answer 1

In Delphi, the special system folder path constants are defined in ShlObj.DCU, and are referenced in the form of CSIDL_ followed by a symbolic name.
Example:
CSIDL_DESKTOPDIRECTORY returns the
path to the current desktop
CSIDL_PERSONAL is the My Documents directory
CSIDL___LOCAL_APPDATA is the (user name)\Local Settings\Application
Data directory
Here's a quick function that will return the appropriate special folder path when given the symbolic name. Make sure you include the SHLOBJ.DCU unit in your USES statement, and use the following:
function GetSpecialFolderPath(Folder: Integer; CanCreate: Boolean): string;
// Gets path of special system folders
//
// Call this routine as follows:
// GetSpecialFolderPath (CSIDL_PERSONAL, false)
// returns folder as result
//
var
FilePath: array [0..255] of char;
begin
SHGetSpecialFolderPath(0, #FilePath[0], FOLDER, CanCreate);
Result := FilePath;
end;
================================================================
For reference, the constants are as follows:
CSIDL_DESKTOP = $0000; { <desktop> }
CSIDL_INTERNET = $0001; { Internet Explorer (icon on desktop) }
CSIDL_PROGRAMS = $0002; { Start Menu\Programs }
CSIDL_CONTROLS = $0003; { My Computer\Control Panel }
CSIDL_PRINTERS = $0004; { My Computer\Printers }
CSIDL_PERSONAL = $0005; { My Documents. This is equivalent to CSIDL_MYDOCUMENTS in XP and above }
CSIDL_FAVORITES = $0006; { <user name>\Favorites }
CSIDL_STARTUP = $0007; { Start Menu\Programs\Startup }
CSIDL_RECENT = $0008; { <user name>\Recent }
CSIDL_SENDTO = $0009; { <user name>\SendTo }
CSIDL_BITBUCKET = $000a; { <desktop>\Recycle Bin }
CSIDL_STARTMENU = $000b; { <user name>\Start Menu }
CSIDL_MYDOCUMENTS = $000c; { logical "My Documents" desktop icon }
CSIDL_MYMUSIC = $000d; { "My Music" folder }
CSIDL_MYVIDEO = $000e; { "My Video" folder }
CSIDL_DESKTOPDIRECTORY = $0010; { <user name>\Desktop }
CSIDL_DRIVES = $0011; { My Computer }
CSIDL_NETWORK = $0012; { Network Neighborhood (My Network Places) }
CSIDL_NETHOOD = $0013; { <user name>\nethood }
CSIDL_FONTS = $0014; { windows\fonts }
CSIDL_TEMPLATES = $0015;
CSIDL_COMMON_STARTMENU = $0016; { All Users\Start Menu }
CSIDL_COMMON_PROGRAMS = $0017; { All Users\Start Menu\Programs }
CSIDL_COMMON_STARTUP = $0018; { All Users\Startup }
CSIDL_COMMON_DESKTOPDIRECTORY = $0019; { All Users\Desktop }
CSIDL_APPDATA = $001a; { <user name>\Application Data }
CSIDL_PRINTHOOD = $001b; { <user name>\PrintHood }
CSIDL_LOCAL_APPDATA = $001c; { <user name>\Local Settings\Application Data (non roaming) }
CSIDL_ALTSTARTUP = $001d; { non localized startup }
CSIDL_COMMON_ALTSTARTUP = $001e; { non localized common startup }
CSIDL_COMMON_FAVORITES = $001f;
CSIDL_INTERNET_CACHE = $0020;
CSIDL_COOKIES = $0021;
CSIDL_HISTORY = $0022;
CSIDL_COMMON_APPDATA = $0023; { All Users\Application Data }
CSIDL_WINDOWS = $0024; { GetWindowsDirectory() }
CSIDL_SYSTEM = $0025; { GetSystemDirectory() }
CSIDL_PROGRAM_FILES = $0026; { C:\Program Files }
CSIDL_MYPICTURES = $0027; { C:\Program Files\My Pictures }
CSIDL_PROFILE = $0028; { USERPROFILE }
CSIDL_SYSTEMX86 = $0029; { x86 system directory on RISC }
CSIDL_PROGRAM_FILESX86 = $002a; { x86 C:\Program Files on RISC }
CSIDL_PROGRAM_FILES_COMMON = $002b; { C:\Program Files\Common }
CSIDL_PROGRAM_FILES_COMMONX86 = $002c; { x86 C:\Program Files\Common on RISC }
CSIDL_COMMON_TEMPLATES = $002d; { All Users\Templates }
CSIDL_COMMON_DOCUMENTS = $002e; { All Users\Documents }
CSIDL_COMMON_ADMINTOOLS = $002f; { All Users\Start Menu\Programs\Administrative Tools }
CSIDL_ADMINTOOLS = $0030; { <user name>\Start Menu\Programs\Administrative Tools }
CSIDL_CONNECTIONS = $0031; { Network and Dial-up Connections }
CSIDL_COMMON_MUSIC = $0035; { All Users\My Music }
CSIDL_COMMON_PICTURES = $0036; { All Users\My Pictures }
CSIDL_COMMON_VIDEO = $0037; { All Users\My Video }
CSIDL_RESOURCES = $0038; { Resource Directory }
CSIDL_RESOURCES_LOCALIZED = $0039; { Localized Resource Directory }
CSIDL_COMMON_OEM_LINKS = $003a; { Links to All Users OEM specific apps }
CSIDL_CDBURN_AREA = $003b; { USERPROFILE\Local Settings\Application Data\Microsoft\CD Burning }
CSIDL_COMPUTERSNEARME = $003d; { Computers Near Me (computered from Workgroup membership) }
CSIDL_PROFILES = $003e;

Answer 2

See this article.
Edit:
As added in the comment by stukelly there is a lot more information available about the SHGetFolderPath() functionality. The Delphi VCL really should have functionality for getting standard paths, and if Embarcadero is indeed going to have another Delphi-like tool on another OS this will be all the more important. For a multi-platform implementation of system standard paths see also the documentation of wxStandardPaths in wxWidgets. On MSW this uses the various CSIDL_XXX constants.

Answer 3

Assuming you can make WinAPI calls from Delphi (which ISTR you can), you used to be able to do that with an API call (something like GetSystemFolder or GetUserDataFolder). It's been a while since I've had to do that, but I think you can now do it with SHGetFolderPath, by passing in CSIDL_LOCAL_APPDATA.