UnauthorizedAccessException cannot resolve Directory.GetFiles failure

Question

Hi all,

Directory.GetFiles method fails on the first encounter with a folder it has no access rights to.

The method throws an UnauthorizedAccessException (which can be caught) but by the time this is done, the method has already failed/terminated.

The code I am using is listed below:

        try
        {
            // looks in stated directory and returns the path of all files found                
            getFiles = Directory.GetFiles(@directoryToSearch, filetype, SearchOption.AllDirectories);             
        }
        catch (UnauthorizedAccessException) { }

As far as I am aware, there is no way to check beforehand whether a certain folder has access rights defined.

In my example, I'm searching on a disk across a network and when I come across a root access only folder, my program fails.

I have searched for a few days now for any sort of resolve, but this problem doesn't seem to be very prevalent on here or Google.

I look forward to any suggestions you may have, Regards

Answer 1

In order to gain control on the level that you want, you should probably probe one directory at a time, instead of a whole tree. The following method populates the given IList<string> with all files found in the directory tree, except those where the user doesn't have access:

// using System.Linq
private static void AddFiles(string path, IList<string> files)
{
    try
    {
        Directory.GetFiles(path)
            .ToList()
            .ForEach(s => files.Add(s));

        Directory.GetDirectories(path)
            .ToList()
            .ForEach(s => AddFiles(s, files));
    }
    catch (UnauthorizedAccessException ex)
    {
        // ok, so we are not allowed to dig into that directory. Move on.
    }
}

Answer 2

In .NET 4 this becomes a lot easier, see http://msdn.microsoft.com/en-us/library/dd997370.aspx