C# Help needed changing code that deletes folders with long paths

Question

Hi all,

A while back I asked a question on stackoverflow about deleting folders that have long paths (>260 characters), the most popular solution was to move into each directory to reduce the length of the path. I've struggled with this and I'm no further on, could someone please suggest how I would intergrate the suggested code into my code?

A typical path is:

\\serverName\share\dave\Private\Careers\Careers Ed\Fun Careers Education\Chris's not used 2006 to07\old 4.Careers Area Activity Week 1 30.10.06 or 6.11.06 or 13.11.06 Introduction to job levels and careers resources\Occupational Areas & Job levels Tutor Help Sheet[1].doc

Many thanks

//Suggested code:

var curDir = Directory.GetCurrentDirectory();
Environment.CurrentDirectory = @"C:\Part\Of\The\Really\Long\Path";
Directory.Delete("Relative\Path\To\Directory");
Environment.CurrentDirectory = curDir;

//My code:

try
 {
     var dir = new DirectoryInfo(@FolderPath);
     dir.Attributes = dir.Attributes & ~FileAttributes.ReadOnly;
     dir.Delete();
 }
 catch (IOException ex)
 {
     MessageBox.Show(ex.Message,"Delete Error",MessageBoxButtons.OK,MessageBoxIcon.Error);
 }

Answer 1

Before 'removing a directory' we have to be sure that it is empty. You could consider using the reverse 'directory walk' approach.

This would entail dealing with each directory seperately in deep-to-shallow order.

Some pseudo code;

While (fullPath.Length > 0)
{
    DirectoryToDelete = GetLastPartOfPath( fullPath );
    CurrentDirectory = fullPath - DirectoryToDelete;

    ChangeDirectory(CurrentDirectory);
    DeleteDirectory(DirectoryToDelete);

    fullPath = fullPath - DirectoryToDelete;
}

Hope this helps,

Answer 2

Have you tried using the long path name syntax ? From the CreateFile function in the platform SDK:

Maximum Path Length In the Windows API (with some exceptions discussed later), the maximum length for a path is MAX_PATH, which is defined as 260 characters. A local path is structured in the following order: drive letter, colon, backslash, components separated by backslashes, and a terminating null character. For example, the maximum path on drive D is "D:\<256 chars>NUL".

The Windows API has many functions that also have Unicode versions to permit a maximum path length of approximately 32,000 characters composed of components up to 255 characters each in length. To specify that kind of extended length path, use the "\?\" prefix. For example, "\?\D:\".

Note The maximum path of 32,000 characters is approximate, because the "\?\" prefix can be expanded to a longer string, and the expansion applies to the total length.

To specify such a path using UNC, use the "\?\UNC\" prefix. For example, "\?\UNC\\". These prefixes are not used as part of the path itself. They indicate that the path should be passed to the system with minimal modification, which means that you cannot use forward slashes to represent path separators, or a period to represent the current directory. Also, you cannot use the "\?\" prefix with a relative path. Relative paths are limited to MAX_PATH characters.

The last paragraph is of course the one that is relevant to your case.

It is not sure that .NET supports this kind of path. You could use P/Invoke to call RemoveDirectory from the Win32 SDK.