Question

I am using C# 4.5 and I’m trying to scan a fileshare for all folders. I want to skip any folder I cannot access and just continue. What I have done is to do it recursively, this throws a stackoverflow. I understand why this happens. So my question is: are there any work arounds?

How would you implemented this since we cannot use recursive search? Are there any third-party libraries I can use to simplify this? GetFolder function is only extracting some information and return a custom class, this works fine.

public void GetFoldersFromFS(string filePath)
{
   if (filePath == null)
   {
      return;
   }

   Directory.SetCurrentDirectory(filePath);
   try
   {
       foreach (var directory in Directory.EnumerateDirectories(Directory.GetCurrentDirectory()))
       {
           Resources.Add(GetFolder(new DirectoryInfo(directory)));
           GetFoldersFromFS(directory);
       }
   }
   catch (UnauthorizedAccessException e)
   {
      Log.Warn(e.Message);
   }
   catch (PathTooLongException e)
   {
      Log.Warn(e.Message);
   }
}

Answer 1

1. Make a list for the directories that you need to do (the to-do-list).
2. Initially, add the single directory (on the share) to the to-do-list.
3. Take the first directory from the list and scan it.
4. When you scan a directory, add any subdirectories to the to-do-list (at the end of the list).
5. Go back to 3 until the to-do-list is empty.

Voila, scanning without recursion.

Pseudo code (without any try-catch):

public List<string> ScanDirectory(string directory) {
    var toDoList = new Queue<string>();
    var result = new List<string>();
    toDoList.Enqueue(directory);

    // Keep going while there is anything to do
    while (toDoList.Count > 0) {
        // Get next directory-to-scan, and add it to the result
        var currentDir = toDoList.Dequeue();
        result.Add(currentDir);
        // Get sub directories
        var subDirectories = new DirectoryInfo(currentDir).GetDirectories();    // TODO: Add any other criteria you want to check
        // Add the sub directories to the to-do list
        foreach (var subDirectory in subDirectories) {
            toDoList.Enqueue(subDirectory);
        }
    }

    // Return all found directories
    return result;
}