/*
 MainWindow.xaml
<Window x:Class="PhotoViewer.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="211" Width="563">
    <Grid>
        <ListBox x:Name="PhotoListBox" ScrollViewer.CanContentScroll="False" ScrollViewer.HorizontalScrollBarVisibility="Auto" ScrollViewer.VerticalScrollBarVisibility="Disabled">
            <ListBox.ItemsPanel>
                <ItemsPanelTemplate>
                    <StackPanel Orientation="Horizontal" Height="{Binding PhotoListBox.Height}" />
                </ItemsPanelTemplate>
            </ListBox.ItemsPanel>
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <Grid Margin="20" >
                        <Grid.RowDefinitions>
                            <RowDefinition Height="*"/>
                            <RowDefinition Height="Auto"/>
                        </Grid.RowDefinitions>
                        <Image Source="{Binding FilePath}" HorizontalAlignment="Center" />
                        <TextBlock Grid.Row="1" Text="{Binding Caption}" HorizontalAlignment="Center"/>
                    </Grid>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
    </Grid>
</Window>
*/

using System;
using System.Collections.ObjectModel;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using System.Windows;

namespace PhotoViewer
{
    /// <summary>
    /// MainWindow.xaml の相互作用ロジック
    /// </summary>
    public partial class MainWindow : Window
    {
        private ObservableCollection<PhotoInfo> photos = new ObservableCollection<PhotoInfo>();

        public MainWindow()
        {
            InitializeComponent();
            this.Loaded += MainWindow_Loaded;
            this.PhotoListBox.ItemsSource = photos;
        }

        private static bool IsImageFile(string fileName)
        {
            // 適当
            var ext = Path.GetExtension(fileName).ToLowerInvariant();
            return ext == ".png" || ext == ".jpg";
        }

        private void MainWindow_Loaded(object sender, RoutedEventArgs e)
        {
            Task.Factory.StartNew(() =>
            {
                foreach (var path in Directory.EnumerateFiles(".").Where(IsImageFile))
                {
                    Dispatcher.BeginInvoke(new Action(() =>
                    {
                        photos.Add(new PhotoInfo
                        {
                            FilePath = Path.GetFullPath(path)
                        });
                    }));
                }
            });
        }
    }

    public class PhotoInfo
    {
        public string FilePath { get; set; }

        public string Caption
        {
            get
            {
                return Path.GetFileName(FilePath);
            }
        }
    }
}