How to sort items of a list by name within his index?

I've order my items by name in a list but i have a problem selecting using the SelectedIndex the item is not the same as selected

for (int i = 0; i < storageList.GetFileNames().Length; i++)
            {
               
                filesbyname.Add(storageList.GetFileNames()[i]);
            }
            var byName = from name in filesbyname orderby name.ToString().ToLower() select name;
            _LirycListBox.ItemsSource = byName;

private void _LirycListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            if (_LirycListBox.SelectedItem != null)
            {
                NavigationService.Navigate(new Uri(string.Format("/EditorSongLiryc.xaml?filename={0}", storageList.GetFileNames()[_LirycListBox.SelectedIndex]), UriKind.Relative));
            }
        }