How to pass through the 260 characters path limit

Question

I'm currently using the .Net Framework and the C# for a project.

I would like to know how to remove the 260 characters limit of the path.

I've tried to go to the regedit ans the gpedit but nothing worked. I've tried to put the "\?" prefix but the path was unrecongnised.

Here a sample of the C# code :

 private static void DirectoryCopy(string sourceDirName, string destDirName, bool copySubDirs)
    {
        // Get the subdirectories for the specified directory.
        DirectoryInfo dir = new DirectoryInfo(sourceDirName);

        if (!dir.Exists)
        {
            throw new DirectoryNotFoundException(
                "Le répertoire source n'existe pas ou n'est pas accessible : "
                + sourceDirName);
        }

        DirectoryInfo[] dirs = dir.GetDirectories();
        // If the destination directory doesn't exist, create it.
        if (!Directory.Exists(destDirName))
        {
            Directory.CreateDirectory(destDirName);
        }

        // Get the files in the directory and copy them to the new location.
        FileInfo[] files = dir.GetFiles();
        foreach (FileInfo file in files)
        {
            temppath = Path.Combine(destDirName, file.Name);
            try
            {
                file.CopyTo(temppath, false);
            }
            catch (Exception ex)
            {
                Erreurs.Add(ex.Message);
                Erreurs.Add(temppath);
            }

        }

        // If copying subdirectories, copy them and their contents to new location.
        if (copySubDirs)
        {
            /*Utility.NetworkDrive.MapNetworkDrive("R", @"\\unc\path");
            var dirs1 = Directory.GetDirectories("R:");
            Utility.NetworkDrive.DisconnectNetworkDrive("R", true);*/
            foreach (DirectoryInfo subdir in dirs)
            {
               temppath = Path.Combine(destDirName, subdir.Name);

              // string fullpath = @"\\?\" + subdir.FullName;  -- HERE'S WHAT I'VE TRIED


                try
                {
                    
                    string sousdoss = subdir.FullName;
                    string loclogic = Application.StartupPath + @"\Xcopy.bat";

                    System.Diagnostics.Process proc = new System.Diagnostics.Process();
                    proc.StartInfo.FileName = Application.StartupPath + @"\Xcopy.bat";

                    proc.StartInfo.Arguments = String.Format("{0} {1} {2}",loclogic, sousdoss, temppath);
                    //set the rest of the process settings
                    proc.Start();                        
                }
                catch(Exception ex)
                {
                    Erreurs.Add(ex.Message);

                }
            }
        }
    }

And here's my batch code (I would like to pass 'loclogic' and 'sousdoss' to %1 and %2) :

xcopy "%1" "%2" /c /h /e /r /y /s

Thanks for your help !

Answer 1

Updated: as pointed out by @Panagiotis Kanavos:

" A path that starts with \?.... can address volumes, streams, snapshots and be up to 32K long."

You can Enable Long Paths in Windows 10, Version 1607, and Later

But as the article describes it is an opt-in feature.

Starting in Windows 10, version 1607, MAX_PATH limitations have been removed from common Win32 file and directory functions. However, you must opt-in to the new behavior.

To enable the new long path behavior, both of the following conditions must be met:

The registry key Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem\LongPathsEnabled (Type: REG_DWORD) must exist and be set to 1. The key's value will be cached by the system (per process) after the first call to an affected Win32 file or directory function (see below for the list of functions). The registry key will not be reloaded during the lifetime of the process. In order for all apps on the system to recognize the value of the key, a reboot might be required because some processes may have started before the key was set.