private void RenameDep_Click(object sender, RoutedEventArgs e)
        {
            var dep = (tv.SelectedItem as TreeViewItem).DataContext;

            RenameDep renameDep = new RenameDep(this, dep);

            renameDep.Show();
        }
        private void RenameEmpl(object sender, RoutedEventArgs e)
        {
            //var dep = (Departament)employees_lv.DataContext;
            //var dep = (tv.SelectedItem as TreeViewItem).DataContext;

            var empl = employees_lv.SelectedItem;

            RenameDep renameDep = new RenameDep(this, empl);

            renameDep.Show();
        }