private void hairdressers_btn_Click(object sender, RoutedEventArgs e)
{
HairdressersPanel hairdressers_panel = new HairdressersPanel();
center_panel.Children.Clear();
center_panel.Children.Add(hairdressers_panel);
}
private void FillDataGrid()
{
HairdressersPanel h = new HairdressersPanel();
main.Children.Clear();
main.Children.Add(h);
}