private async void NextStep_Click(object sender, RoutedEventArgs args)
        {
            /**
             * handle checking account process HERE.
             *
             * 1.check the textbox NotNull
             */

            var txtAcc = txtBoxAcc.Text;

            if (txtAcc == null || txtAcc == "")
            {
                return;
            }
            var isPhoneNum = RegexTool.IsMobilePhone(txtAcc);

            System.Diagnostics.Debug.WriteLine(txtAcc);
            System.Diagnostics.Debug.WriteLine(isPhoneNum);
            if (!RegexTool.IsMobilePhone(txtAcc))
            {
                await new ContentDialog()
                {
                    Title           = "这个手机号无效",
                    CloseButtonText = "确认",
                    DefaultButton   = ContentDialogButton.Close
                }.ShowAsync();
                return;
            }

            PlayAccGotoPass();
        }