C# Remove all empty subdirectories

Question

I have a task to clean up a large number of directories. I want to start at a directory and delete any sub-directories (no matter how deep) that contain no files (files will never be deleted, only directories). The starting directory will then be deleted if it contains no files or subdirectories. I was hoping someone could point me to some existing code for this rather than having to reinvent the wheel. I will be doing this using C#.

Answer 1

From here, Powershell script to remove empty directories:

$items = Get-ChildItem -Recurse

foreach($item in $items)
{
      if( $item.PSIsContainer )
      {
            $subitems = Get-ChildItem -Recurse -Path $item.FullName
            if($subitems -eq $null)
            {
                  "Remove item: " + $item.FullName
                  Remove-Item $item.FullName
            }
            $subitems = $null
      }
}

Note: use at own risk!

Answer 2

In C#:

       static void Main(string[] args)
    {
        processDirectory(@"c:\temp");
    }

    private static void processDirectory(string startLocation)
    {
        foreach (var directory in Directory.GetDirectories(startLocation))
        {
            processDirectory(directory);
            if (Directory.GetFiles(directory).Length == 0 && Directory.GetDirectories(directory).Length == 0)
            {
                Directory.Delete(directory, false);
            }
        }
    }

Answer 3

If you can target the .NET 4.0 you can use the new methods on the Directory class to enumerate the directories in order to not pay a performance penalty in listing every file in a directory when you just want to know if there is at least one.

The methods are:

• Directory.EnumerateDirectories
• Directory.EnumerateFiles
• Directory.EnumerateFileSystemEntries

A possible implementation using recursion:

static void Main(string[] args)
{
    DeleteEmptyDirs("Start");
}

static void DeleteEmptyDirs(string dir)
{
    if (String.IsNullOrEmpty(dir))
        throw new ArgumentException(
            "Starting directory is a null reference or an empty string", 
            "dir");

    try
    {
        foreach (var d in Directory.EnumerateDirectories(dir))
        {
            DeleteEmptyDirs(d);
        }

        var entries = Directory.EnumerateFileSystemEntries(dir);

        if (!entries.Any())
        {
            try
            {
                Directory.Delete(dir);
            }
            catch (UnauthorizedAccessException) { }
            catch (DirectoryNotFoundException) { }
        }
    }
    catch (UnauthorizedAccessException) { }
}

You also mention that the directory tree could be very deep so it's possible you might get some exceptions if the path you are probing are too long.