private void btnCamKet_Click(object sender, EventArgs e)
        {
            try
            {
                string           idContract       = this.txtIDContract.Text.Trim();
                string           idCustomer       = this.dgv_CusThue.CurrentRow.Cells[0].Value.ToString().Trim();
                string           idVehicle        = this.lbBienSo.Text.Trim();
                DateTime         dateSign         = this.dtPicker1.Value;
                float            totalCost        = float.Parse(this.txtCost.Text.Trim());
                string           idEmployee       = Global.GlobalEmployeeId;
                contract_ThueDTO contract_ThueDTO = new contract_ThueDTO(idContract, idCustomer, idVehicle, dateSign, totalCost, idEmployee);

                if (this.contract_ThueBUS.insertContract_Thue(contract_ThueDTO))
                {
                    MessageBox.Show("Thêm hợp đồng thành công", "Contract Thuê", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    this.LoadVehicleChoThue_DGV();
                }
                else
                {
                    MessageBox.Show("Thêm hợp đồng không thành công", "Contract Thuê", MessageBoxButtons.OK, MessageBoxIcon.Error);
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show("Error: " + ex.Message);
            }
        }
        //insert
        public bool insertContract_Thue(contract_ThueDTO contract_ThueDTO)
        {
            try
            {
                this.openConnection();

                SqlCommand cmd = new SqlCommand("INSERT INTO CONTRACT_THUE(id, idCustomer, idVehicle, dateSign, TotalCost, idEmployee)" +
                                                "VALUES (@id1, @id2, @id3, @ds, @TotalCost, @idEmployee)", this.getConnection);
                cmd.Parameters.Add("@id1", SqlDbType.NChar).Value        = contract_ThueDTO.id;
                cmd.Parameters.Add("@id2", SqlDbType.NChar).Value        = contract_ThueDTO.idCustomer;
                cmd.Parameters.Add("@id3", SqlDbType.NChar).Value        = contract_ThueDTO.idVehicle;
                cmd.Parameters.Add("@ds", SqlDbType.Date).Value          = contract_ThueDTO.dateSign;
                cmd.Parameters.Add("@TotalCost", SqlDbType.Float).Value  = contract_ThueDTO.TotalCost;
                cmd.Parameters.Add("@idEmployee", SqlDbType.NChar).Value = contract_ThueDTO.idEmployee;

                if (cmd.ExecuteNonQuery() == 1)
                {
                    return(true);
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show("Error:1 ", ex.Message);
            }
            finally
            {
                this.closeConnection();
            }
            return(false);
        }
 //insert
 public bool insertContract_Thue(contract_ThueDTO contract_ThueDTO)
 {
     return(this.contract_ThueDAL.insertContract_Thue(contract_ThueDTO));
 }