Ignore folder C# (System.UnauthorizedAccessException)

Question

A quick question. I'm executing this code:

listBox1.Items.AddRange( Directory.GetDirectories("C:\\Users\\", "*" ,SearchOption.AllDirectories));

It list all directories and subdirectories in C:\\Users\\ (yes I know, it maybe blow up my pc)

Anyways, I am getting this error (System.UnauthorizedAccessException)

This error comes from the special folders "C:\\Users\\All Users\\" and "C:\\Users\\USER\\AppData\\"

How can I ignore this folders to program keeping listing all dir and subd without Exceptions?

Answer 1

Unfortunately it's not possible to filter out all directories without the required permissions. You need to implement your own recursive function to deal with the problem by catching the UnauthorizedAccessException . Since there could be many exceptions the way is not very fast but reliable like explained in this question :

[...] permissions (even file existence) are volatile — they can change at any time [...]

Here is my possible solution:

public static void GetDirectories(string path, Action<string> foundDirectory)
{
    string[] dirs;
    try
    {
        dirs = Directory.GetDirectories(path, "*", SearchOption.TopDirectoryOnly);
    }
    catch (UnauthorizedAccessException)
    {
        //Ignore a directory if an unauthorized access occured
        return;
    }

    foreach (string dir in dirs)
    {
        foundDirectory(dir);
        //Recursive call to get all subdirectories
        GetDirectories(dir, foundDirectory);
    }
}

Simply call the function like

List<string> allDirectories = new List<string>();
GetDirectories(@"C:\Users\", d => allDirectories.Add(d));