private void btn_View_Edit_inv_Click(object sender, EventArgs e)
        {
            try
            {
                int    selected_Inv_ID = Convert.ToInt16(dgv_search.CurrentRow.Cells[0].Value);
                string sup_name        = (dgv_search.CurrentRow.Cells[8].Value).ToString();

                frm_Purchase_Invoice frm_edit = new frm_Purchase_Invoice("Edit", sup_name, selected_Inv_ID);
                frm_edit.ShowDialog();
            }
            catch (Exception exp)
            {
                MessageBox.Show(exp.Message);
            }
        }
        private void button2_Click(object sender, EventArgs e)
        {
            frm_Purchase_Invoice new_pur_inv = new frm_Purchase_Invoice("Add");

            new_pur_inv.ShowDialog();
        }