private void button6_Click(object sender, EventArgs e)
{
BusCart busCart = new BusCart(Bus.buss.ElementAt(listBox3.SelectedIndex));
busCart.Show();
busCart.FormClosing += (object sender1, FormClosingEventArgs e1) => RefreshCells();
}
private void button4_Click(object sender, EventArgs e)
{
Bus newBus = new Bus();
Bus.buss.Add(newBus);
BusCart busCart = new BusCart(newBus);
busCart.Show();
busCart.FormClosing += (object sender1, FormClosingEventArgs e1) => RefreshCells();
}