how get directories read only ? c#

i use this code to select a path and get all subdirectories of it

if (FBD_devis.ShowDialog() == DialogResult.OK)
{
try
{
DirectoryInfo diri_info = new DirectoryInfo(FBD_devis.SelectedPath); listBox2.Items.AddRange(diri_info.GetDirectories("*", SearchOption.AllDirectories));
}
catch (UnauthorizedAccessException u)
{
MessageBox.Show("le problème c'est a cause ce Dossiers: " + u.Message + "\n" + u.Source);
}
}

but when i select the path

it generate this problem

how can I fix this problem please ?