private void Button_Click(object sender, RoutedEventArgs e)
        {
            dataAccess data  = new dataAccess();
            DataTable  table = new DataTable();

            table = data.getInvoices();
            if (table.Rows.Count < 0)
            {
                MessageBox.Show("History");
            }
            else
            {
                historyGrid.ItemsSource = table.DefaultView;
            }
        }