private void BtnActivate_OnClick(object sender, RoutedEventArgs e)
        {
            string key = tbKey.Text;

            if (string.IsNullOrWhiteSpace(key))
            {
                tbInfo.Text = "请输入有效许可证。";
                return;
            }
            var lisence = DataContext as SimpleLicense;

            if (lisence != null && LisenceTool.ToProductCodeFormat(lisence.LicenseKey) == key)
            {
                tbInfo.Text = "此许可证已经被使用了, 请更换新的许可证。";
                return;
            }


            if (LisenceService.UpdateLisence(key))
            {
                tbInfo.Text = "更新许可证成功,请关闭此窗口。";
                Lisenced    = true;
            }

            else
            {
                tbInfo.Text = "更新许可证失败, 请联系您的软件供应商。";
            }
        }
        private void LisenceWindow_OnLoaded(object sender, RoutedEventArgs e)
        {
            tbSN.Text = LisenceTool.ToProductCodeFormat(SnProvider.CalculateSN());
            var lisence = DataContext as SimpleLicense;

            if (lisence != null)
            {
                tbKey.Text = LisenceTool.ToProductCodeFormat(lisence.LicenseKey);
                if (lisence.IsExpired)
                {
                    tbInfo.Text        = "您的许可证已经到期,请联系您的软件供应商获取新的许可证。";
                    btnTrial.IsEnabled = false;
                }

                int days = (lisence.ExpireDateTime - DateTime.Now).Days + 1;
                tbInfo.Text        = string.Format("您的许可证还有{0}天到期,请及时联系您的软件供应商获取新的许可证。", days);
                btnTrial.IsEnabled = false;
            }
        }