问如何使用XAML和C#从Windows phone8中的文件夹创建图片库？

EN

public static List<PhotoItem> GetPhotos()
{
    return new List<PhotoItem>()
    {
        new PhotoItem(){PhotoName="Image1",Photo = new BitmapImage(new Uri("/Images/Image1.jpg", UriKind.Relative))},
        new PhotoItem(){PhotoName="Image2",Photo = new BitmapImage(new Uri("/Images/Image2.jpg", UriKind.Relative))},
    };
}

public class PhotoItemViewModel : INotifyPropertyChanged
    {
        private ObservableCollection<PhotoItem> photoList;
        public ObservableCollection<PhotoItem> PhotoList
        {
            get
            {
                return photoList;
            }
            set
            {
                photoList = value;
                NotifyPropertyChanged();
            }
        }

        public void LoadData()
        {
            PhotoList = new ObservableCollection<PhotoItem>(PhotoItem.GetPhotos());
        }

        public event PropertyChangedEventHandler PropertyChanged;
        public void NotifyPropertyChanged([CallerMemberName] string propertyName = null)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }

   <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
        <phone:LongListSelector ItemsSource="{Binding PhotoList}">
            <phone:LongListSelector.ItemTemplate>
                <DataTemplate>
                    <StackPanel>
                        <TextBlock Text="{Binding PhotoName}"></TextBlock>
                        <Image Source="{Binding Photo}"></Image>
                    </StackPanel>
                </DataTemplate>
            </phone:LongListSelector.ItemTemplate>
        </phone:LongListSelector>
    </Grid>

 public MainPage()
        {
            InitializeComponent();
            this.Loaded += MainPage_Loaded;
        }

        void MainPage_Loaded(object sender, RoutedEventArgs e)
        {
            viewModel.LoadData();
            DataContext = viewModel;
        }