private void cmdModifyDuressFP_Click(object sender, EventArgs e)
        {
            int  vEnrollNumber;
            int  vFingerNumber;
            int  vDuressSetting;
            bool bRet;
            int  vErrorCode = 0;

            lblMessage.Text = "Working...";
            Application.DoEvents();

            bRet = bpc.EnableDevice(Program.gMachineNumber, 0); // 0 : disable
            if (!bRet)
            {
                lblMessage.Text = util.gstrNoDevice;
                return;
            }

            vEnrollNumber  = Convert.ToInt32(txtEnrollNumber.Text);
            vFingerNumber  = Convert.ToInt32(cmbBackupNumber.Text);
            vDuressSetting = Convert.ToInt32(cmbDuressSetting.Text);

            bRet = bpc.ModifyDuressFP(Program.gMachineNumber,
                                      vEnrollNumber,
                                      vFingerNumber,
                                      vDuressSetting
                                      );
            if (bRet)
            {
                lblMessage.Text = "ModifyDuressFP OK";
            }
            else
            {
                bpc.GetLastError(ref vErrorCode);
                lblMessage.Text = util.ErrorPrint(vErrorCode);
            }

            bRet = bpc.EnableDevice(Program.gMachineNumber, 1); // 1 : enable
        }