private async void btnDelete_Click(object sender, RoutedEventArgs e)
        {
            if (lsvUser.SelectedItem == null)
            {
                await InfoDialog.ShowOK("请选择需要删除指纹信息的人员。");

                return;
            }

            if ((lsvUser.SelectedItem as custPerDisplayItem).FID != "")
            {
                if (await InfoDialog.ShowYesNo("确定删除指定人员的指纹信息吗?") == ContentDialogResult.Secondary)
                {
                    return;
                }

                await GPIOControl.PowerOnFingerprintPower( );

                try
                {
                    // Delete from fingerprint device
                    fgRemoveFingerprint cmd = new fgRemoveFingerprint(Convert.ToUInt16((lsvUser.SelectedItem as custPerDisplayItem).FID.Trim( )));
                    CommonResult        ret = await FingerprintDevice.Execute(cmd);

                    // Update compare file
                    await StorageControl.UpdateFIDByPID((lsvUser.SelectedItem as custPerDisplayItem).PID, string.Empty);
                    await LoadFingprinterInfo( );
                }
                catch (Exception ex)
                {
                    throw new CommonResult(ResultCode.GN_SYS_ERROR, ex.Message);
                }
                finally
                {
                    GPIOControl.PowerOffFingerprintPower( );
                }
            }
            else
            {
                await InfoDialog.ShowOK("指定的人员没有记录指纹信息。");
            }
        }
 private void Dialog_Closing(ContentDialog sender, ContentDialogClosingEventArgs args)
 {
     GPIOControl.PowerOffFingerprintPower( );
 }