DeleteWithPrejudice and Purge

public static void DeleteWithPrejudice(this DirectoryInfo directoryInfo)
{
    directoryInfo.DeleteWithPrejudice(true);
}

public static void Purge(this DirectoryInfo directoryInfo)
{
    directoryInfo.DeleteWithPrejudice(false);
}

private static void DeleteWithPrejudice(this DirectoryInfo directoryInfo, bool deleteRoot)
{

    /* Determine whether the directory exists */
    if (!directoryInfo.RefreshExists())
    {
        return;
    }
    directoryInfo.Refresh();
    /* Remove Readonly, System, and Hidden attributes prior to deletion */
    directoryInfo.Attributes = FileAttributes.Directory;

    directoryInfo.DeleteAllFiles(true);

    var folderPaths = new List<DirectoryInfo>();

    foreach (var subDirectory in directoryInfo.GetDirectories("*", SearchOption.AllDirectories))
    {
        folderPaths.Add(subDirectory);
    }
    if (deleteRoot)
    {
        folderPaths.Add(directoryInfo);
    }

    // sort has a side effect that means the deepest directories will be at the top
    folderPaths.Sort((x, y) => y.FullName.CompareTo(x.FullName));

    foreach (var folderPath in folderPaths)
    {
        if (!folderPath.RefreshExists())
        {
            continue;
        }
        folderPath.Attributes = directoryInfo.Attributes & ~ReadOnlyHiddenSystemFileAttributes;
        folderPath.Refresh();
        folderPath.Delete();
    }
}

directoryToDelete.DeleteWithPrejudice();