由于 Environment.GetFolderPath 可以传入的参数里面，有许多都是 Windows 系统特有的，在 Linux 上不存在的，也没有映射对应的文件夹。本文将在 WSL Debian 和 UOS 系统上测试 Environment.GetFolderPath 行为
测试使用 Environment.SpecialFolder 的各个枚举获取路径的代码如下
foreach (var name in Enum.GetNames<Environment.SpecialFolder>()) { Console.WriteLine($"{name} = {Environment.GetFolderPath(Enum.Parse<Environment.SpecialFolder>(name))}"); }在 WSL Debian 的运行结果如下
Desktop =Programs =MyDocuments =Personal =Favorites =Startup =Recent =SendTo =StartMenu =MyMusic =MyVideos =DesktopDirectory =MyComputer =NetworkShortcuts =Fonts =Templates =CommonStartMenu =CommonPrograms =CommonStartup =CommonDesktopDirectory =ApplicationData = /home/user/.configPrinterShortcuts =LocalApplicationData = /home/user/.local/shareInternetCache =Cookies =History =CommonApplicationData = /usr/shareWindows =System =ProgramFiles =MyPictures =UserProfile = /home/userSystemX86 =ProgramFilesX86 =CommonProgramFiles =CommonProgramFilesX86 =CommonTemplates =CommonDocuments =CommonAdminTools =AdminTools =CommonMusic =CommonPictures =CommonVideos =Resources =LocalizedResources =CommonOemLinks =CDBurning =在 UOS 系统的运行结果如下
Desktop = /home/lin/DesktopPrograms =MyDocuments = /home/lin/DocumentsPersonal = /home/lin/DocumentsFavorites =Startup =Recent =SendTo =StartMenu =MyMusic = /home/lin/MusicMyVideos = /home/lin/VideosDesktopDirectory = /home/lin/DesktopMyComputer =NetworkShortcuts =Fonts =Templates = /home/lin/.TemplatesCommonStartMenu =CommonPrograms =CommonStartup =CommonDesktopDirectory =ApplicationData = /home/lin/.configPrinterShortcuts =LocalApplicationData = /home/lin/.local/shareInternetCache =Cookies =History =CommonApplicationData = /usr/shareWindows =System =ProgramFiles =MyPictures = /home/lin/PicturesUserProfile = /home/linSystemX86 =ProgramFilesX86 =CommonProgramFiles =CommonProgramFilesX86 =CommonTemplates =CommonDocuments =CommonAdminTools =AdminTools =CommonMusic =CommonPictures =CommonVideos =Resources =LocalizedResources =CommonOemLinks =CDBurning =可以看到 UOS 上有更多的属性是存在值的，存在一些行为差异
另外，根据 UOS 官方文档 的如下说明：
软件包不允许直接向$HOME目录直接写入文件，后期系统将会使用沙箱技术重新定向$HOME,任何依赖该特性的行为都可能失效。 应用使用如下环境变量指示的目录写入应用数据和配置：
$XDG_DATA_HOME $XDG_CONFIG_HOME $XDG_CACHE_HOME对于appid为org.deepin.browser的应用，其写入目录为：
$XDG_DATA_HOME/org.deepin.browser $XDG_CONFIG_HOME/org.deepin.browser $XDG_CACHE_HOME/org.deepin.browser我同时也测试了以上的 XDG_DATA_HOME 和 XDG_CONFIG_HOME 和 XDG_CACHE_HOME 环境变量的内容，在我的设备上的输出如下
XDG_DATA_HOME = /home/lin/.local/shareXDG_CONFIG_HOME = /home/lin/.configXDG_CACHE_HOME = /home/lin/.cache可以看到 XDG_DATA_HOME 和 LocalApplicationData 是对应的值。而 XDG_CONFIG_HOME 和 ApplicationData 是对应的值
可以通过如下方式获取本文的源代码，先创建一个空文件夹，接着使用命令行 cd 命令进入此空文件夹，在命令行里面输入以下代码，即可获取到本文的代码
git initgit remote add origin https://gitee.com/lindexi/lindexi_gd.gitgit pull origin 61a7e77b8b86e17ccf2b5d1a9d0460d09cc95036以上使用的是 gitee 的源，如果 gitee 不能访问，请替换为 github 的源。请在命令行继续输入以下代码
git remote remove origingit remote add origin https://github.com/lindexi/lindexi_gd.gitgit pull origin 61a7e77b8b86e17ccf2b5d1a9d0460d09cc95036获取代码之后，进入 NurbeakairweWaharbaner 文件夹
这里的 XDG 是 X Desktop Group 的缩写，更多 XDG 知识请参阅：
在 dotnet 的 runtime 底层的 Environment.GetFolderPath 实现如下
public static partial class Environment { private static string GetFolderPathCore(SpecialFolder folder, SpecialFolderOption option) { // Get the path for the SpecialFolder string path = GetFolderPathCoreWithoutValidation(folder) ?? string.Empty; Debug.Assert(path != null);
// If we didn't get one, or if we got one but we're not supposed to verify it, // or if we're supposed to verify it and it passes verification, return the path. if (path.Length == 0 || option == SpecialFolderOption.DoNotVerify || Interop.Sys.Access(path, Interop.Sys.AccessMode.R_OK) == 0) { return path; }
// Failed verification. If None, then we're supposed to return an empty string. // If Create, we're supposed to create it and then return the path. if (option == SpecialFolderOption.None) { return string.Empty; }
Debug.Assert(option == SpecialFolderOption.Create);
Directory.CreateDirectory(path);
return path; }
private static string? GetFolderPathCoreWithoutValidation(SpecialFolder folder) { // First handle any paths that involve only static paths, avoiding the overheads of getting user-local paths. // https://www.freedesktop.org/software/systemd/man/file-hierarchy.html switch (folder) { case SpecialFolder.CommonApplicationData: return "/usr/share"; case SpecialFolder.CommonTemplates: return "/usr/share/templates";#if TARGET_OSX case SpecialFolder.ProgramFiles: return "/Applications"; case SpecialFolder.System: return "/System";#endif }
// All other paths are based on the XDG Base Directory Specification: // https://specifications.freedesktop.org/basedir-spec/latest/ string? home = null; try { home = PersistedFiles.GetHomeDirectory(); } catch (Exception exc) { Debug.Fail($"Unable to get home directory: {exc}"); }
// Fall back to '/' when we can't determine the home directory. // This location isn't writable by non-root users which provides some safeguard // that the application doesn't write data which is meant to be private. if (string.IsNullOrEmpty(home)) { home = "/"; }
// TODO: Consider caching (or precomputing and caching) all subsequent results. // This would significantly improve performance for repeated access, at the expense // of not being responsive to changes in the underlying environment variables, // configuration files, etc.
switch (folder) { case SpecialFolder.UserProfile: return home;
case SpecialFolder.Templates: return ReadXdgDirectory(home, "XDG_TEMPLATES_DIR", "Templates"); // TODO: Consider merging the OSX path with the rest of the Apple systems here: // https://github.com/dotnet/runtime/blob/main/src/libraries/System.Private.CoreLib/src/System/Environment.iOS.cs#if TARGET_OSX case SpecialFolder.Desktop: case SpecialFolder.DesktopDirectory: return Interop.Sys.SearchPath(NSSearchPathDirectory.NSDesktopDirectory); case SpecialFolder.ApplicationData: case SpecialFolder.LocalApplicationData: return Interop.Sys.SearchPath(NSSearchPathDirectory.NSApplicationSupportDirectory); case SpecialFolder.MyDocuments: // same value as Personal return Interop.Sys.SearchPath(NSSearchPathDirectory.NSDocumentDirectory); case SpecialFolder.MyMusic: return Interop.Sys.SearchPath(NSSearchPathDirectory.NSMusicDirectory); case SpecialFolder.MyVideos: return Interop.Sys.SearchPath(NSSearchPathDirectory.NSMoviesDirectory); case SpecialFolder.MyPictures: return Interop.Sys.SearchPath(NSSearchPathDirectory.NSPicturesDirectory); case SpecialFolder.Fonts: return Path.Combine(home, "Library", "Fonts"); case SpecialFolder.Favorites: return Path.Combine(home, "Library", "Favorites"); case SpecialFolder.InternetCache: return Interop.Sys.SearchPath(NSSearchPathDirectory.NSCachesDirectory);#else case SpecialFolder.Desktop: case SpecialFolder.DesktopDirectory: return ReadXdgDirectory(home, "XDG_DESKTOP_DIR", "Desktop"); case SpecialFolder.ApplicationData: return GetXdgConfig(home); case SpecialFolder.LocalApplicationData: // "$XDG_DATA_HOME defines the base directory relative to which user specific data files should be stored." // "If $XDG_DATA_HOME is either not set or empty, a default equal to $HOME/.local/share should be used." string? data = GetEnvironmentVariable("XDG_DATA_HOME"); if (data is null || !data.StartsWith('/')) { data = Path.Combine(home, ".local", "share"); } return data; case SpecialFolder.MyDocuments: // same value as Personal return ReadXdgDirectory(home, "XDG_DOCUMENTS_DIR", "Documents"); case SpecialFolder.MyMusic: return ReadXdgDirectory(home, "XDG_MUSIC_DIR", "Music"); case SpecialFolder.MyVideos: return ReadXdgDirectory(home, "XDG_VIDEOS_DIR", "Videos"); case SpecialFolder.MyPictures: return ReadXdgDirectory(home, "XDG_PICTURES_DIR", "Pictures"); case SpecialFolder.Fonts: return Path.Combine(home, ".fonts");#endif }
// No known path for the SpecialFolder return string.Empty; }
private static string GetXdgConfig(string home) { // "$XDG_CONFIG_HOME defines the base directory relative to which user specific configuration files should be stored." // "If $XDG_CONFIG_HOME is either not set or empty, a default equal to $HOME/.config should be used." string? config = GetEnvironmentVariable("XDG_CONFIG_HOME"); if (config is null || !config.StartsWith('/')) { config = Path.Combine(home, ".config"); } return config; }
private static string ReadXdgDirectory(string homeDir, string key, string fallback) { Debug.Assert(!string.IsNullOrEmpty(homeDir), $"Expected non-empty homeDir"); Debug.Assert(!string.IsNullOrEmpty(key), $"Expected non-empty key"); Debug.Assert(!string.IsNullOrEmpty(fallback), $"Expected non-empty fallback");
string? envPath = GetEnvironmentVariable(key); if (envPath is not null && envPath.StartsWith('/')) { return envPath; }
// Use the user-dirs.dirs file to look up the right config. // Note that the docs also highlight a list of directories in which to look for this file: // "$XDG_CONFIG_DIRS defines the preference-ordered set of base directories to search for configuration files in addition // to the $XDG_CONFIG_HOME base directory. The directories in $XDG_CONFIG_DIRS should be separated with a colon ':'. If // $XDG_CONFIG_DIRS is either not set or empty, a value equal to / etc / xdg should be used." // For simplicity, we don't currently do that. We can add it if/when necessary.
string userDirsPath = Path.Combine(GetXdgConfig(homeDir), "user-dirs.dirs"); if (Interop.Sys.Access(userDirsPath, Interop.Sys.AccessMode.R_OK) == 0) { try { using (var reader = new StreamReader(userDirsPath)) { string? line; while ((line = reader.ReadLine()) != null) { // Example lines: // XDG_DESKTOP_DIR="$HOME/Desktop" // XDG_PICTURES_DIR = "/absolute/path"
// Skip past whitespace at beginning of line int pos = 0; SkipWhitespace(line, ref pos); if (pos >= line.Length) continue;
// Skip past requested key name if (string.CompareOrdinal(line, pos, key, 0, key.Length) != 0) continue; pos += key.Length;
// Skip past whitespace and past '=' SkipWhitespace(line, ref pos); if (pos >= line.Length - 4 || line[pos] != '=') continue; // 4 for ="" and at least one char between quotes pos++; // skip past '='
// Skip past whitespace and past first quote SkipWhitespace(line, ref pos); if (pos >= line.Length - 3 || line[pos] != '"') continue; // 3 for "" and at least one char between quotes pos++; // skip past opening '"'
// Skip past relative prefix if one exists bool relativeToHome = false; const string RelativeToHomePrefix = "$HOME/"; if (string.CompareOrdinal(line, pos, RelativeToHomePrefix, 0, RelativeToHomePrefix.Length) == 0) { relativeToHome = true; pos += RelativeToHomePrefix.Length; } else if (line[pos] != '/') // if not relative to home, must be absolute path { continue; }
// Find end of path int endPos = line.IndexOf('"', pos); if (endPos <= pos) continue;
// Got we need. Now extract it. string path = line.Substring(pos, endPos - pos); return relativeToHome ? Path.Combine(homeDir, path) : path; } } } catch (Exception exc) { // assembly not found, file not found, errors reading file, etc. Just eat everything. Debug.Fail($"Failed reading {userDirsPath}: {exc}"); } }
return Path.Combine(homeDir, fallback); }
private static void SkipWhitespace(string line, ref int pos) { while (pos < line.Length && char.IsWhiteSpace(line[pos])) pos++; } }注： 在 dotnet 6.0.26 和 dotnet 7 版本，获取的 MyDocuments 的值将会和 UserProfile 相同，都是指向 $HOME 环境变量的路径，如以下代码
case SpecialFolder.UserProfile: case SpecialFolder.MyDocuments: // same value as Personal return home;更详细的代码如下
private static string GetFolderPathCoreWithoutValidation(SpecialFolder folder) { // First handle any paths that involve only static paths, avoiding the overheads of getting user-local paths. // https://www.freedesktop.org/software/systemd/man/file-hierarchy.html switch (folder) { case SpecialFolder.CommonApplicationData: return "/usr/share"; case SpecialFolder.CommonTemplates: return "/usr/share/templates";#if TARGET_OSX case SpecialFolder.ProgramFiles: return "/Applications"; case SpecialFolder.System: return "/System";#endif }
// All other paths are based on the XDG Base Directory Specification: // https://specifications.freedesktop.org/basedir-spec/latest/ string? home = null; try { home = PersistedFiles.GetHomeDirectory(); } catch (Exception exc) { Debug.Fail($"Unable to get home directory: {exc}"); }
// Fall back to '/' when we can't determine the home directory. // This location isn't writable by non-root users which provides some safeguard // that the application doesn't write data which is meant to be private. if (string.IsNullOrEmpty(home)) { home = "/"; }
// TODO: Consider caching (or precomputing and caching) all subsequent results. // This would significantly improve performance for repeated access, at the expense // of not being responsive to changes in the underlying environment variables, // configuration files, etc.
switch (folder) { case SpecialFolder.UserProfile: case SpecialFolder.MyDocuments: // same value as Personal return home; case SpecialFolder.ApplicationData: return GetXdgConfig(home); case SpecialFolder.LocalApplicationData: // "$XDG_DATA_HOME defines the base directory relative to which user specific data files should be stored." // "If $XDG_DATA_HOME is either not set or empty, a default equal to $HOME/.local/share should be used." string? data = GetEnvironmentVariable("XDG_DATA_HOME"); if (string.IsNullOrEmpty(data) || data[0] != '/') { data = Path.Combine(home, ".local", "share"); } return data;
case SpecialFolder.Desktop: case SpecialFolder.DesktopDirectory: return ReadXdgDirectory(home, "XDG_DESKTOP_DIR", "Desktop"); case SpecialFolder.Templates: return ReadXdgDirectory(home, "XDG_TEMPLATES_DIR", "Templates"); case SpecialFolder.MyVideos: return ReadXdgDirectory(home, "XDG_VIDEOS_DIR", "Videos");
#if TARGET_OSX case SpecialFolder.MyMusic: return Path.Combine(home, "Music"); case SpecialFolder.MyPictures: return Path.Combine(home, "Pictures"); case SpecialFolder.Fonts: return Path.Combine(home, "Library", "Fonts"); case SpecialFolder.Favorites: return Path.Combine(home, "Library", "Favorites"); case SpecialFolder.InternetCache: return Path.Combine(home, "Library", "Caches");#else case SpecialFolder.MyMusic: return ReadXdgDirectory(home, "XDG_MUSIC_DIR", "Music"); case SpecialFolder.MyPictures: return ReadXdgDirectory(home, "XDG_PICTURES_DIR", "Pictures"); case SpecialFolder.Fonts: return Path.Combine(home, ".fonts");#endif }
// No known path for the SpecialFolder return string.Empty; }在 dotnet 8 的 Fix some incorrect SpecialFolder entries for Unix by Miepee · Pull Request #68610 · dotnet/runtime 的更改里面，优化了各路径的读取方法，从而更改了 MyDocuments 的返回值路径
详细文档请看 .NET 8 中断性变更：Unix 上的 GetFolderPath 行为 - .NET Microsoft Learn
以上不仅变更了在 Linux 上的行为也变更了在安卓 macOS 等的行为
本作品采用 知识共享署名-非商业性使用-相同方式共享 4.0 国际许可协议 进行许可。 欢迎转载、使用、重新发布，但务必保留文章署名 林德熙 (包含链接: https://blog.lindexi.com )，不得用于商业目的，基于本文修改后的作品务必以相同的许可发布。如有任何疑问，请与我 联系。