A .NET library to access files and directories with more than 260 characters length.

This article describes a library that provides several classes and functions to perform basic functions on file paths and folder paths that are longer than the "MAX_PATH" limit of 260 characters.

All .NET functions I cam accross that access the file system are limited to file paths and folder paths with less than 260 characters. This includes most (all?) of the classes in the System.IO namespace like e.g. the System.IO.FileInfo class.

Since I was in the need to actually access paths with more than 260 characters, I searched for a solution. Fortunately a solution exists; basically you have to P/Invoke Win32 functions that allow a special syntax to prefix a file and allow it then to be much longer than the 260 characters (about 32,000 characters).

So I started writing a very thin wrapper for the functions I required to work on long file names.

These resources helped me finding more:

• "Long Paths in .NET" on the BCL Team Blog.
• pinvoke.net for finding signatures of Win32 functions.
• Using long path syntax with UNC, MSDN.

I started by using several functions from the BCL Team blog postings and added the functions they did not cover but which I needed in my project.

Currently there are the following classes:

• ZlpFileInfo - A class similar to System.IO.FileInfo that wraps functions to work on file paths.
• ZlpDirectoryInfo - A class similar to System.IO.DirectoryInfo that wraps functions to work on folder paths.
• ZlpIOHelper - A set of static functions to provide similar features as the ZlpFileInfo and ZlpDirectoryInfo class but in a static context.
• ZlpPathHelper - A set of static functions similar to System.IO.Path that work on paths.

The project contains some unit tests to show basic functions.

If you are familiar with the System.IO namespace, you should be able to use the classes of the library.

For example to get all files in a given folder path, use the following snippet:

var folderPath = new ZetaDirectoryInfo( @"C:\My\Long\Folder\Path" );
 
foreach ( var filePath in folderPath.GetFiles() )
{
    Console.Write( "File {0} has a size of {1}", 
        filePath.FullName, 
        filePath.Length );
}

Beside this library, there are other libraries available for accessing longer paths:

• Long Path from the BCL CodePlex library.
• Delimon.Win32.IO Library from the Microsoft TechNet Gallery.
• QuickIO.NET
• AlphaFS

Personally, I've used none of these libraries. When I started developing this library either none of the other libraries existed or I have poorly searched.

According to user comments, the Long Path library is rather restricted in terms of functionality; the Delimon library is apparently much more powerful than my library.

This article quickly introduced a library to deal with long file names when accessing files and folders.

Please note that the library currently is limited in the number of provided functions. I will add more functions in the future, just tell me which you require.

I'm using the library in several widely used real-life projects like our CMS, our Test Management tool or our Large File Uploader, so the library should be rather stable and reliable.

• 2014-09-18 - Added functions like MoveFileToRecycleBin() to delete files and folders by moving them to the recycle bin.
• 2014-06-25 - First release to GitHub. Also available at The Code Project.
• 2012-12-21 - Added an NuGet package.
• 2012-09-20 - Some very few methods added. Stability release.
• 2012-08-10 - Added several new methods.
• 2011-10-11 - Fixed an issue inside ZlpFileInfo.Exists.
• 2011-01-31 - Added functions MoveFile and MoveDirectory.
• 2010-03-24 - Added functions to get file owner, creation time, last access time, last write time.
• 2010-02-16 - Maintenance release.
• 2009-11-25 - First release to CodePlex.com.