C# .NET 不支持长路径Long Path（260字符限制）,指定的路径或文件名太长,或者两者都太长的解决方法
在存有新建文件夹并可以拖拽功能的情况下，发现连环套入出现问题
“指定的路径或文件名太长,或者两者都太长。完全限定文件名必须少于 260”
方法一:
但是这个需要.NET 4.6.2 及以上
因为需求是要基于4.0，所以Pass。
方法二:
通过使用widows API进行解决
internal static class NativeMethods { internal const int FILE_ATTRIBUTE_ARCHIVE = 0x20; internal const int INVALID_FILE_ATTRIBUTES = -1; internal const int FILE_READ_DATA = 0x0001; internal const int FILE_WRITE_DATA = 0x0002; internal const int FILE_APPEND_DATA = 0x0004; internal const int FILE_READ_EA = 0x0008; internal const int FILE_WRITE_EA = 0x0010; internal const int FILE_READ_ATTRIBUTES = 0x0080; internal const int FILE_WRITE_ATTRIBUTES = 0x0100; internal const int FILE_SHARE_NONE = 0x00000000; internal const int FILE_SHARE_READ = 0x00000001; internal const int FILE_ATTRIBUTE_DIRECTORY = 0x10; internal const long FILE_GENERIC_WRITE = STANDARD_RIGHTS_WRITE | FILE_WRITE_DATA | FILE_WRITE_ATTRIBUTES | FILE_WRITE_EA | FILE_APPEND_DATA | SYNCHRONIZE; internal const long FILE_GENERIC_READ = STANDARD_RIGHTS_READ | FILE_READ_DATA | FILE_READ_ATTRIBUTES | FILE_READ_EA | SYNCHRONIZE; internal const long READ_CONTROL = 0x00020000L; internal const long STANDARD_RIGHTS_READ = READ_CONTROL; internal const long STANDARD_RIGHTS_WRITE = READ_CONTROL; internal const long SYNCHRONIZE = 0x00100000L; internal const int CREATE_NEW = 1; internal const int CREATE_ALWAYS = 2; internal const int OPEN_EXISTING = 3; internal const int MAX_PATH = 260; internal const int MAX_ALTERNATE = 14; [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] internal struct WIN32_FIND_DATA { public System.IO.FileAttributes dwFileAttributes; public FILETIME ftCreationTime; public FILETIME ftLastAccessTime; public FILETIME ftLastWriteTime; public uint nFileSizeHigh; //changed all to uint, otherwise you run into unexpected overflow public uint nFileSizeLow; //| public uint dwReserved0; //| public uint dwReserved1; //v [MarshalAs(UnmanagedType.ByValTStr, SizeConst = MAX_PATH)] public string cFileName; [MarshalAs(UnmanagedType.ByValTStr, SizeConst = MAX_ALTERNATE)] public string cAlternate; } [DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)] internal static extern SafeFileHandle CreateFile(string lpFileName, int dwDesiredAccess, int dwShareMode, IntPtr lpSecurityAttributes, int dwCreationDisposition, int dwFlagsAndAttributes, IntPtr hTemplateFile); [DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)] internal static extern bool CopyFileW(string lpExistingFileName, string lpNewFileName, bool bFailIfExists); [DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)] internal static extern int GetFileAttributesW(string lpFileName); [DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)] internal static extern bool DeleteFileW(string lpFileName); [DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)] internal static extern bool MoveFileW(string lpExistingFileName, string lpNewFileName); [DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)] internal static extern bool SetFileTime(SafeFileHandle hFile, ref long lpCreationTime, ref long lpLastAccessTime, ref long lpLastWriteTime); [DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)] internal static extern bool GetFileTime(SafeFileHandle hFile, ref long lpCreationTime, ref long lpLastAccessTime, ref long lpLastWriteTime); [DllImport("kernel32", CharSet = CharSet.Unicode, SetLastError = true)] internal static extern IntPtr FindFirstFile(string lpFileName, out WIN32_FIND_DATA lpFindFileData); [DllImport("kernel32", CharSet = CharSet.Unicode, SetLastError = true)] internal static extern bool FindNextFile(IntPtr hFindFile, out WIN32_FIND_DATA lpFindFileData); [DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)] internal static extern bool FindClose(IntPtr hFindFile); [DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)] internal static extern bool RemoveDirectory(string path); [DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)] internal static extern bool CreateDirectory(string lpPathName, IntPtr lpSecurityAttributes); [DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)] internal static extern int SetFileAttributesW(string lpFileName, int fileAttributes); }
public class LongDirectory { private const int MAX_PATH = 260; public static void CreateDirectory(string path) { if (string.IsNullOrWhiteSpace(path)) return; if (path.Length < MAX_PATH) { System.IO.Directory.CreateDirectory(path); } else { var paths = GetAllPathsFromPath(GetWin32LongPath(path)); foreach (var item in paths) { if (!LongExists(item)) { var ok = NativeMethods.CreateDirectory(item, IntPtr.Zero); if (!ok) { ThrowWin32Exception(); } } } } } public static void Delete(string path) { Delete(path, false); } public static void DeleteT(string path) { Delete(path, true); } public static void Delete(string path, bool recursive) { if (path.Length < MAX_PATH && !recursive) { System.IO.Directory.Delete(path, false); } else { if (!recursive) { bool ok = NativeMethods.RemoveDirectory(GetWin32LongPath(path)); if (!ok) ThrowWin32Exception(); } else { DeleteDirectories(new string[] { GetWin32LongPath(path) }); } } } private static void DeleteDirectories(string[] directories) { foreach (string directory in directories) { string[] files = LongDirectory.GetFiles(directory, null, System.IO.SearchOption.TopDirectoryOnly); foreach (string file in files) { LongFile.Delete(file); } directories = LongDirectory.GetDirectories(directory, null, System.IO.SearchOption.TopDirectoryOnly); DeleteDirectories(directories); bool ok = NativeMethods.RemoveDirectory(GetWin32LongPath(directory)); if (!ok) ThrowWin32Exception(); } } public static bool Exists(string path) { if (path.Length < MAX_PATH) return System.IO.Directory.Exists(path); return LongExists(GetWin32LongPath(path)); } private static bool LongExists(string path) { var attr = NativeMethods.GetFileAttributesW(path); return (attr != NativeMethods.INVALID_FILE_ATTRIBUTES && ((attr & NativeMethods.FILE_ATTRIBUTE_DIRECTORY) == NativeMethods.FILE_ATTRIBUTE_DIRECTORY)); } public static string[] GetDirectories(string path) { return GetDirectories(path, null, SearchOption.TopDirectoryOnly); } public static string[] GetDirectories(string path, string searchPattern) { return GetDirectories(path, searchPattern, SearchOption.TopDirectoryOnly); } public static string[] GetDirectories(string path, string searchPattern, System.IO.SearchOption searchOption) { searchPattern = searchPattern ?? "*"; var dirs = new List<string>(); InternalGetDirectories(path, searchPattern, searchOption, ref dirs); return dirs.ToArray(); } private static void InternalGetDirectories(string path, string searchPattern, System.IO.SearchOption searchOption, ref List<string> dirs) { NativeMethods.WIN32_FIND_DATA findData; IntPtr findHandle = NativeMethods.FindFirstFile(System.IO.Path.Combine(GetWin32LongPath(path), searchPattern), out findData); try { if (findHandle != new IntPtr(-1)) { do { if ((findData.dwFileAttributes & System.IO.FileAttributes.Directory) != 0) { if (findData.cFileName != "." && findData.cFileName != "..") { string subdirectory = System.IO.Path.Combine(path, findData.cFileName); dirs.Add(GetCleanPath(subdirectory)); if (searchOption == SearchOption.AllDirectories) { InternalGetDirectories(subdirectory, searchPattern, searchOption, ref dirs); } } } } while (NativeMethods.FindNextFile(findHandle, out findData)); NativeMethods.FindClose(findHandle); } else { ThrowWin32Exception(); } } catch (Exception) { NativeMethods.FindClose(findHandle); throw; } } public static string[] GetFiles(string path) { return GetFiles(path, null, SearchOption.TopDirectoryOnly); } public static string[] GetFiles(string path, string searchPattern) { return GetFiles(path, searchPattern, SearchOption.TopDirectoryOnly); } public static string[] GetFiles(string path, string searchPattern, System.IO.SearchOption searchOption) { searchPattern = searchPattern ?? "*"; var files = new List<string>(); var dirs = new List<string> { path }; if (searchOption == SearchOption.AllDirectories) { //Add all the subpaths dirs.AddRange(LongDirectory.GetDirectories(path, null, SearchOption.AllDirectories)); } foreach (var dir in dirs) { NativeMethods.WIN32_FIND_DATA findData; IntPtr findHandle = NativeMethods.FindFirstFile(System.IO.Path.Combine(GetWin32LongPath(dir), searchPattern), out findData); try { if (findHandle != new IntPtr(-1)) { do { if ((findData.dwFileAttributes & System.IO.FileAttributes.Directory) == 0) { string filename = System.IO.Path.Combine(dir, findData.cFileName); files.Add(GetCleanPath(filename)); } } while (NativeMethods.FindNextFile(findHandle, out findData)); NativeMethods.FindClose(findHandle); } } catch (Exception) { NativeMethods.FindClose(findHandle); throw; } } return files.ToArray(); } public static void Move(string sourceDirName, string destDirName) { if (sourceDirName.Length < MAX_PATH || destDirName.Length < MAX_PATH) { System.IO.Directory.Move(sourceDirName, destDirName); } else { var ok = NativeMethods.MoveFileW(GetWin32LongPath(sourceDirName), GetWin32LongPath(destDirName)); if (!ok) ThrowWin32Exception(); } } #region Helper methods [DebuggerStepThrough] public static void ThrowWin32Exception() { int code = Marshal.GetLastWin32Error(); if (code != 0) { throw new System.ComponentModel.Win32Exception(code); } } public static string GetWin32LongPath(string path) { if (path.StartsWith(@"\\?\")) return path; var newpath = path; if (newpath.StartsWith("\\")) { newpath = @"\\?\UNC\" + newpath.Substring(2); } else if (newpath.Contains(":")) { newpath = @"\\?\" + newpath; } else { var currdir = Environment.CurrentDirectory; newpath = Combine(currdir, newpath); while (newpath.Contains("\\.\\")) newpath = newpath.Replace("\\.\\", "\\"); newpath = @"\\?\" + newpath; } return newpath.TrimEnd('.'); } private static string GetCleanPath(string path) { if (path.StartsWith(@"\\?\UNC\")) return @"\\" + path.Substring(8); if (path.StartsWith(@"\\?\")) return path.Substring(4); return path; } private static List<string> GetAllPathsFromPath(string path) { bool unc = false; var prefix = @"\\?\"; if (path.StartsWith(prefix + @"UNC\")) { prefix += @"UNC\"; unc = true; } var split = path.Split('\\'); int i = unc ? 6 : 4; var list = new List<string>(); var txt = ""; for (int a = 0; a < i; a++) { if (a > 0) txt += "\\"; txt += split[a]; } for (; i < split.Length; i++) { txt = Combine(txt, split[i]); list.Add(txt); } return list; } private static string Combine(string path1, string path2) { return path1.TrimEnd('\\') + "\\" + path2.TrimStart('\\').TrimEnd('.'); } #endregion }
public static class LongFile { private const int MAX_PATH = 260; public static bool Exists(string path) { if (path.Length < MAX_PATH) return System.IO.File.Exists(path); var attr = NativeMethods.GetFileAttributesW(GetWin32LongPath(path)); return (attr != NativeMethods.INVALID_FILE_ATTRIBUTES && ((attr & NativeMethods.FILE_ATTRIBUTE_ARCHIVE) == NativeMethods.FILE_ATTRIBUTE_ARCHIVE)); } public static void Delete(string path) { if (path.Length < MAX_PATH) System.IO.File.Delete(path); else { bool ok = NativeMethods.DeleteFileW(GetWin32LongPath(path)); if (!ok) ThrowWin32Exception(); } } public static void AppendAllText(string path, string contents) { AppendAllText(path, contents, Encoding.Default); } public static void AppendAllText(string path, string contents, Encoding encoding) { if (path.Length < MAX_PATH) { System.IO.File.AppendAllText(path, contents, encoding); } else { var fileHandle = CreateFileForAppend(GetWin32LongPath(path)); using (var fs = new System.IO.FileStream(fileHandle, System.IO.FileAccess.Write)) { var bytes = encoding.GetBytes(contents); fs.Position = fs.Length; fs.Write(bytes, 0, bytes.Length); } } } public static void WriteAllText(string path, string contents) { WriteAllText(path, contents, Encoding.Default); } public static void WriteAllText(string path, string contents, Encoding encoding) { if (path.Length < MAX_PATH) { System.IO.File.WriteAllText(path, contents, encoding); } else { var fileHandle = CreateFileForWrite(GetWin32LongPath(path)); using (var fs = new System.IO.FileStream(fileHandle, System.IO.FileAccess.Write)) { var bytes = encoding.GetBytes(contents); fs.Write(bytes, 0, bytes.Length); } } } public static void WriteAllBytes(string path, byte[] bytes) { if (path.Length < MAX_PATH) { System.IO.File.WriteAllBytes(path, bytes); } else { var fileHandle = CreateFileForWrite(GetWin32LongPath(path)); using (var fs = new System.IO.FileStream(fileHandle, System.IO.FileAccess.Write)) { fs.Write(bytes, 0, bytes.Length); } } } public static void Copy(string sourceFileName, string destFileName) { Copy(sourceFileName, destFileName, false); } public static void Copy(string sourceFileName, string destFileName, bool overwrite) { if (sourceFileName.Length < MAX_PATH && (destFileName.Length < MAX_PATH)) System.IO.File.Copy(sourceFileName, destFileName, overwrite); else { var ok = NativeMethods.CopyFileW(GetWin32LongPath(sourceFileName), GetWin32LongPath(destFileName), !overwrite); if (!ok) ThrowWin32Exception(); } } public static void Move(string sourceFileName, string destFileName) { if (sourceFileName.Length < MAX_PATH && (destFileName.Length < MAX_PATH)) System.IO.File.Move(sourceFileName, destFileName); else { var ok = NativeMethods.MoveFileW(GetWin32LongPath(sourceFileName), GetWin32LongPath(destFileName)); if (!ok) ThrowWin32Exception(); } } public static string ReadAllText(string path) { return ReadAllText(path, Encoding.Default); } public static string ReadAllText(string path, Encoding encoding) { if (path.Length < MAX_PATH) { return System.IO.File.ReadAllText(path, encoding); } var fileHandle = GetFileHandle(GetWin32LongPath(path)); using (var fs = new System.IO.FileStream(fileHandle, System.IO.FileAccess.Read)) { var data = new byte[fs.Length]; fs.Read(data, 0, data.Length); return encoding.GetString(data); } } public static string[] ReadAllLines(string path) { return ReadAllLines(path, Encoding.Default); } public static string[] ReadAllLines(string path, Encoding encoding) { if (path.Length < MAX_PATH) { return System.IO.File.ReadAllLines(path, encoding); } var fileHandle = GetFileHandle(GetWin32LongPath(path)); using (var fs = new System.IO.FileStream(fileHandle, System.IO.FileAccess.Read)) { var data = new byte[fs.Length]; fs.Read(data, 0, data.Length); var str = encoding.GetString(data); if (str.Contains("\r")) return str.Split(new[] { "\r\n" }, StringSplitOptions.None); return str.Split('\n'); } } public static byte[] ReadAllBytes(string path) { if (path.Length < MAX_PATH) return System.IO.File.ReadAllBytes(path); var fileHandle = GetFileHandle(GetWin32LongPath(path)); using (var fs = new System.IO.FileStream(fileHandle, System.IO.FileAccess.Read)) { var data = new byte[fs.Length]; fs.Read(data, 0, data.Length); return data; } } public static void SetAttributes(string path, FileAttributes attributes) { if (path.Length < MAX_PATH) { System.IO.File.SetAttributes(path, attributes); } else { var longFilename = GetWin32LongPath(path); NativeMethods.SetFileAttributesW(longFilename, (int)attributes); } } #region Helper methods private static SafeFileHandle CreateFileForWrite(string filename) { if (filename.Length >= MAX_PATH) filename = GetWin32LongPath(filename); SafeFileHandle hfile = NativeMethods.CreateFile(filename, (int)NativeMethods.FILE_GENERIC_WRITE, NativeMethods.FILE_SHARE_NONE, IntPtr.Zero, NativeMethods.CREATE_ALWAYS, 0, IntPtr.Zero); if (hfile.IsInvalid) ThrowWin32Exception(); return hfile; } private static SafeFileHandle CreateFileForAppend(string filename) { if (filename.Length >= MAX_PATH) filename = GetWin32LongPath(filename); SafeFileHandle hfile = NativeMethods.CreateFile(filename, (int)NativeMethods.FILE_GENERIC_WRITE, NativeMethods.FILE_SHARE_NONE, IntPtr.Zero, NativeMethods.CREATE_NEW, 0, IntPtr.Zero); if (hfile.IsInvalid) { hfile = NativeMethods.CreateFile(filename, (int)NativeMethods.FILE_GENERIC_WRITE, NativeMethods.FILE_SHARE_NONE, IntPtr.Zero, NativeMethods.OPEN_EXISTING, 0, IntPtr.Zero); if (hfile.IsInvalid) ThrowWin32Exception(); } return hfile; } internal static SafeFileHandle GetFileHandle(string filename) { if (filename.Length >= MAX_PATH) filename = GetWin32LongPath(filename); SafeFileHandle hfile = NativeMethods.CreateFile(filename, (int)NativeMethods.FILE_GENERIC_READ, NativeMethods.FILE_SHARE_READ, IntPtr.Zero, NativeMethods.OPEN_EXISTING, 0, IntPtr.Zero); if (hfile.IsInvalid) ThrowWin32Exception(); return hfile; } internal static SafeFileHandle GetFileHandleWithWrite(string filename) { if (filename.Length >= MAX_PATH) filename = GetWin32LongPath(filename); SafeFileHandle hfile = NativeMethods.CreateFile(filename, (int)(NativeMethods.FILE_GENERIC_READ | NativeMethods.FILE_GENERIC_WRITE | NativeMethods.FILE_WRITE_ATTRIBUTES), NativeMethods.FILE_SHARE_NONE, IntPtr.Zero, NativeMethods.OPEN_EXISTING, 0, IntPtr.Zero); if (hfile.IsInvalid) ThrowWin32Exception(); return hfile; } public static System.IO.FileStream GetFileStream(string filename, FileAccess access = FileAccess.Read) { var longFilename = GetWin32LongPath(filename); SafeFileHandle hfile; if (access == FileAccess.Write) { hfile = NativeMethods.CreateFile(longFilename, (int)(NativeMethods.FILE_GENERIC_READ | NativeMethods.FILE_GENERIC_WRITE | NativeMethods.FILE_WRITE_ATTRIBUTES), NativeMethods.FILE_SHARE_NONE, IntPtr.Zero, NativeMethods.OPEN_EXISTING, 0, IntPtr.Zero); } else { hfile = NativeMethods.CreateFile(longFilename, (int)NativeMethods.FILE_GENERIC_READ, NativeMethods.FILE_SHARE_READ, IntPtr.Zero, NativeMethods.OPEN_EXISTING, 0, IntPtr.Zero); } if (hfile.IsInvalid) ThrowWin32Exception(); return new System.IO.FileStream(hfile, access); } [DebuggerStepThrough] public static void ThrowWin32Exception() { int code = Marshal.GetLastWin32Error(); if (code != 0) { throw new System.ComponentModel.Win32Exception(code); } } public static string GetWin32LongPath(string path) { if (path.StartsWith(@"\\?\")) return path; if (path.StartsWith("\\")) { path = @"\\?\UNC\" + path.Substring(2); } else if (path.Contains(":")) { path = @"\\?\" + path; } else { var currdir = Environment.CurrentDirectory; path = Combine(currdir, path); while (path.Contains("\\.\\")) path = path.Replace("\\.\\", "\\"); path = @"\\?\" + path; } return path.TrimEnd('.'); ; } private static string Combine(string path1, string path2) { return path1.TrimEnd('\\') + "\\" + path2.TrimStart('\\').TrimEnd('.'); ; } #endregion public static void SetCreationTime(string path, DateTime creationTime) { long cTime = 0; long aTime = 0; long wTime = 0; using (var handle = GetFileHandleWithWrite(path)) { NativeMethods.GetFileTime(handle, ref cTime, ref aTime, ref wTime); var fileTime = creationTime.ToFileTimeUtc(); if (!NativeMethods.SetFileTime(handle, ref fileTime, ref aTime, ref wTime)) { throw new Win32Exception(); } } } public static void SetLastAccessTime(string path, DateTime lastAccessTime) { long cTime = 0; long aTime = 0; long wTime = 0; using (var handle = GetFileHandleWithWrite(path)) { NativeMethods.GetFileTime(handle, ref cTime, ref aTime, ref wTime); var fileTime = lastAccessTime.ToFileTimeUtc(); if (!NativeMethods.SetFileTime(handle, ref cTime, ref fileTime, ref wTime)) { throw new Win32Exception(); } } } public static void SetLastWriteTime(string path, DateTime lastWriteTime) { long cTime = 0; long aTime = 0; long wTime = 0; using (var handle = GetFileHandleWithWrite(path)) { NativeMethods.GetFileTime(handle, ref cTime, ref aTime, ref wTime); var fileTime = lastWriteTime.ToFileTimeUtc(); if (!NativeMethods.SetFileTime(handle, ref cTime, ref aTime, ref fileTime)) { throw new Win32Exception(); } } } public static DateTime GetLastWriteTime(string path) { long cTime = 0; long aTime = 0; long wTime = 0; using (var handle = GetFileHandleWithWrite(path)) { NativeMethods.GetFileTime(handle, ref cTime, ref aTime, ref wTime); return DateTime.FromFileTimeUtc(wTime); } } }
这个方法相当好用，如果你只需要用到这些方法，那就直接使用就行。不然就需要自行增加了
方法三:
.NET 4.6.2以下版本在App.config里配置，就行了
<configuration>
<runtime>
<AppContextSwitchOverrides value="Switch.System.IO.UseLegacyPathHandling=false;Switch.System.IO.BlockLongPaths=false" />
</runtime>
</configuration>
有条件的可以自行查阅https://stackoverflow.com/questions/5188527/how-to-deal-with-files-with-a-name-longer-than-259-characters
也可以看看这位的https://www.cnblogs.com/q1a0mu/p/13205531.html,只是没有方法二
