WPF 页面切换效果

最近做一个有页面切换的吧..

我觉得这个功能是比较基础的吧..

在网上百度了一下..

用NavigationWindow的比较好..

因为Demo中是带了淡入淡出的页面效果的..

我就想研究一下这个效果是怎么实现的..

发现找不到..

 public partial class MainWindow : NavigationWindow
    {
        public MainWindow()
        {
            InitializeComponent();
        }
        private void NavigationWindow_Navigating(object sender, NavigatingCancelEventArgs e)
        {
            if (Content != null && !_allowDirectNavigation)
            {
                e.Cancel = true;
                _navArgs = e;
                this.IsHitTestVisible = false;
                DoubleAnimation da = new DoubleAnimation(0.3d, new Duration(TimeSpan.FromMilliseconds(100)));
                da.Completed += FadeOutCompleted;
                this.BeginAnimation(OpacityProperty, da);
            }
            _allowDirectNavigation = false;
        }

        private void FadeOutCompleted(object sender, EventArgs e)
        {
            (sender as AnimationClock).Completed -= FadeOutCompleted;

            this.IsHitTestVisible = true;

            _allowDirectNavigation = true;
            switch (_navArgs.NavigationMode)
            {
                case NavigationMode.New:
                    if (_navArgs.Uri == null)
                    {
                        NavigationService.Navigate(_navArgs.Content);
                    }
                    else
                    {
                        NavigationService.Navigate(_navArgs.Uri);
                    }
                    break;
                case NavigationMode.Back:
                    NavigationService.GoBack();
                    break;

                case NavigationMode.Forward:
                    NavigationService.GoForward();
                    break;
                case NavigationMode.Refresh:
                    NavigationService.Refresh();
                    break;
            }

            Dispatcher.BeginInvoke(DispatcherPriority.Loaded,
                (ThreadStart)delegate()
                {
                    DoubleAnimation da = new DoubleAnimation(1.0d, new Duration(TimeSpan.FromMilliseconds(200)));
                    this.BeginAnimation(OpacityProperty, da);
                });
        }

        private bool _allowDirectNavigation = false;
        private NavigatingCancelEventArgs _navArgs = null;
    }