private void del_Btn_Click(object sender, EventArgs e)
        {
            if (dataGridView1.SelectedRows.Count > 0)
            {
                int index  = dataGridView1.SelectedRows[0].Index;
                int id     = (int)dataGridView1.Rows[index].Cells["ID"].Value;
                var result = MessageBox.Show("Are you sure want to deleted this techinician?", "Warning!", MessageBoxButtons.YesNo);

                if (result == DialogResult.Yes)
                {
                    Technician technician = GData.technicians.Where(t => t.id == id).ToList()[0];
                    if (DatabaseControl.deleteTechnician(technician))
                    {
                        MessageBox.Show("Selected Technician has been deleted!");
                        showTechnicians();
                    }
                }
                else
                {
                    return;
                }
            }
        }