how to get files from directory in list_box1 to list_box2?

Question

I could get the directories (2012 ,2014...) and put them in a listbox1.

`DirectoryInfo[] diri_info =new DirectoryInfo(FBD.SelectedPath).GetDirectories();

foreach (DirectoryInfo dir in diri_info)
{
listBox1.Items.Add(dir);

}

, And I tried to also get the files in a directory selected And display them in the listbox 2 and open selected file but files dosn't appear , how fix that please ?

private void listBox2_SelectedIndexChanged(object sender, EventArgs e)
{

DirectoryInfo dirictory_choisis =(DirectoryInfo)listBox1.SelectedItem;

FileInfo[] files = dirictory_choisis.GetFiles();


foreach (FileInfo file in files)
{
listBox2.Items.Add(file.FullName);

}
}
}
}

[1]: https://i.stack.imgur.com/rmtZH.png