void Camera_AutoFocusCompleted(object sender, CameraOperationCompletedEventArgs e)
        {
            var luminance = new PhotoCameraLuminanceSource(this.CameraW, this.CameraH);

            this.Camera.GetPreviewBufferY(luminance.PreviewBufferY);
            luminance.Cutout((int)this.RR.Left, (int)this.RR.Top, (int)this.RR.Width, (int)this.RR.Height);
            var result = this.Reader.Decode(luminance);


            //this.Tip = result != null ? result.Text : DateTime.Now.ToString("不能识别 HH:mm:ss");
            if (result != null)
            {
                VibrateController.Default.Start(new TimeSpan(0, 0, 0, 0, 200));
                this.IsScanning        = false;
                this.ScanBtnVisibility = Visibility.Visible;
                this.Tip = result.Text;
                this.NotifyOfPropertyChange(() => this.Tip);
                this.NotifyOfPropertyChange(() => this.IsScanning);
                this.NotifyOfPropertyChange(() => this.ScanBtnVisibility);
            }
            else
            {
                this.SetFocus();
            }
        }
        void Camera_AutoFocusCompleted(object sender, CameraOperationCompletedEventArgs e)
        {
            var luminance = new PhotoCameraLuminanceSource(this.CameraW, this.CameraH);

            this.Camera.GetPreviewBufferY(luminance.PreviewBufferY);
            luminance.Cutout((int)this.RR.Left, (int)this.RR.Top, (int)this.RR.Width, (int)this.RR.Height);
            var result = this.Reader.Decode(luminance);

            Deployment.Current.Dispatcher.BeginInvoke(() => {
                if (result != null)
                {
                    this.Tip.Text = result.Text;
                }
                else
                {
                    this.Tip.Text = "未识别" + DateTime.Now.ToString("HH:mm:ss");
                }
            });
        }