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Handle Long Paths in .NET

, 15 Sep 2011 CPOL
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A class written to easily handle long paths (32K in length) using .NET.

Introduction

This class allows for easy access to long path names in Windows. This is useful if you've ever run into exceptions because the path you're trying to access is too long. Your applications will no longer be limited by the 250~ character length limit.

Background

I set out to build a project in my free time. I won't get into the details but, I was stopped in my tracks, my plan ruined by the max length limit. Fortunately, I found the article series Long Paths in .NET, Part 1 of 3 [Kim Hamilton]. I used ideas from that article series to come to this simple solution to my problem.

Using the Code

I tried to emulate some of the functionality and method names of the File and Directory classes in the System.IO namespace as closely as possible. The namespace is System.IO.LongPath. The two classes are File and Directory.

The File class contains the following public methods:

  • void Delete(string file)
  • Deletes the specified file.

  • FileStream Open(string path, System.IO.FileMode mode, System.IO.FileAccess access, System.IO.FileShare share)
  • Opens a file stream to the file specified in the path argument.

  • void Copy(string sourceFile, string destinationFile, bool failIfDestinationExists)
  • Copies a file from one location to another.

  • void Move(string sourceFile, string destinationFile, bool failIfDestinationExists)
  • Moves a file from one location to another.

The Directory class contains the following public methods:

  • void Create(string directory)
  • Creates a directory with the given name.

  • void Delete(string drectory)
  • Deletes the specified directory and all sub-directories and files.

  • bool Exists(string drectory)
  • Checks if the specified directory exists.

  • string[] GetFileSystemEntries(string drectory)
  • Gets file system entries for the directory provided by the directory argument. This is not a recursive function, only file system entries for the provided directory are returned.

Points of Interest

This is the largest venture I've made into the Windows API. I don't know exactly what I'm doing. For example, I copied the attribute:

[return: MarshalAs(UnmanagedType.Bool)]

I copied this from Kim Hamilton's article and used it on the additional bool functions I imported from the Windows API. I don't know if I should be doing that or not. Feedback on that would be interesting.

You must specify all paths as long name paths by using \\?\c:\long\path and network paths as \\?\UNC\server\long\path.

You may not use relative paths. All paths specified must be absolute. ".." and "." are not supported.

I'm interested in any feedback. Please share your thoughts with me.

History

  • 2011-09-14 - First submission.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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About the Author

Nathan Stiles
Web Developer
United States United States
No Biography provided

Comments and Discussions

 
Questionlong path Pinmemberandrewop pit25-Sep-14 7:59 
SuggestionFindFirstFileEx Pinmemberkornman0030-Jun-14 3:03 
SuggestionVery nice PinmemberNavy037712-Sep-13 3:08 
Questionhow to delete long path file Pinmemberrockybart18-Jan-13 19:46 
QuestionRe: how to delete long path file PinmemberNathan Stiles24-Jan-13 16:35 
Is this tool somehow usable from code? Does it have an API? Is source available?
QuestionAnother one PinmemberRichard Deeming22-Sep-11 6:38 
AnswerRe: Another one Pinmemberdrweb8627-Sep-11 23:30 
GeneralRe: Another one PinmemberRichard Deeming19-Oct-11 9:13 

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