XAMLを使わないWPF入門36「ListViewでMVVM」

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>WinExe</OutputType>
    <TargetFramework>net9.0-windows</TargetFramework>
    <Nullable>enable</Nullable>
    <ImplicitUsings>enable</ImplicitUsings>
    <UseWPF>true</UseWPF>
  </PropertyGroup>

</Project>

using System;
using System.Windows;

namespace FileSelector02;

public class App : Application
{
    [STAThread]
    public static void Main(string[] args)
    {
        var app = new App();
        app.Run();
    }

    protected override void OnStartup(StartupEventArgs e)
    {
        base.OnStartup(e);
        var win = new MainWindow();
        win.Show();
    }
}

using System.Windows;

[assembly:ThemeInfo(
    ResourceDictionaryLocation.None,            //where theme specific resource dictionaries are located
                                                //(used if a resource is not found in the page,
                                                // or application resource dictionaries)
    ResourceDictionaryLocation.SourceAssembly   //where the generic resource dictionary is located
                                                //(used if a resource is not found in the page,
                                                // app, or any theme specific resource dictionaries)
)]

using System.ComponentModel;
using System.Runtime.CompilerServices;

namespace FileSelector02;

public abstract class ObservableObject : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler? PropertyChanged;

    protected bool Set<T>(ref T field, T value, [CallerMemberName] string? name = null)
    {
        if (Equals(field, value)) return false;
        field = value;
        OnPropertyChanged(name);
        return true;
    }

    protected void OnPropertyChanged([CallerMemberName] string? name = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));
    }
}

using System;
using System.Windows.Input;

namespace FileSelector02;

public sealed class RelayCommand : ICommand
{
    private readonly Action<object?> _exec;
    private readonly Func<object?, bool>? _can;
    public RelayCommand(Action<object?> exec, Func<object?, bool>? can = null)
    { _exec = exec; _can = can; }
    public bool CanExecute(object? p) => _can?.Invoke(p) ?? true;
    public void Execute(object? p) => _exec(p);
    public event EventHandler? CanExecuteChanged;
    public void RaiseCanExecuteChanged() => CanExecuteChanged?.Invoke(this, EventArgs.Empty);
}

using System.ComponentModel;

public abstract class ViewModelBase : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler? PropertyChanged;
    protected void OnPropertyChanged([System.Runtime.CompilerServices.CallerMemberName] string? name = null)
        => PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));
}

namespace FileSelector02;

public class FileSelectorItem
{
    public string DisplayName { get; set; } = "";
    public string FullPath { get; set; } = "";
    public bool IsDir { get; set; }
    public bool IsUpEntry { get; set; }   // 追加: 「..」専用フラグ
    public long Size { get; set; }

    public override string ToString() => DisplayName;
}

using System.IO;

namespace FileSelector02;
public sealed class FileSystemService : IFileSystemService
{
    public IEnumerable<FileSelectorItem> Enumerate(string dir)
    {
        // "__root__" なら論理ドライブ一覧を返す（IsReady==true のみ）
        if (string.Equals(dir, "__root__", StringComparison.OrdinalIgnoreCase))
        {
            foreach (var dv in DriveInfo.GetDrives())
            {
                bool ready = false;
                try { ready = dv.IsReady; } catch { ready = false; }
                if (!ready) continue;

                string display = dv.Name; // "C:\\"
                try
                {
                    if (!string.IsNullOrEmpty(dv.VolumeLabel))
                        display = $"{dv.Name} ({dv.VolumeLabel})";
                }
                catch { /* ラベル取得で例外になる環境は無視 */ }

                long size = 0;
                try { size = dv.TotalSize; } catch { /* 権限等で取れない場合は0 */ }

                yield return new FileSelectorItem
                {
                    DisplayName = display,
                    FullPath = dv.RootDirectory.FullName, // 例: "C:\\"
                    IsDir = true,
                    Size = size, // TotalSize を表示（不要なら 0 でもOK）
                    
                };
            }
            yield break;
        }

        // ここから通常ディレクトリ
        DirectoryInfo cur;
        try { cur = new DirectoryInfo(dir); }
        catch { yield break; }

        var parent = cur.Parent;
        if (parent != null)
        {
            // 通常の親へ戻る ".."
            yield return new FileSelectorItem
            {
                DisplayName = "..",
                FullPath = parent.FullName,
                IsDir = true,
                Size = 0,
                IsUpEntry = true,     // ← 追加
            };
        }
        else
        {
            // ドライブ直下 (例: C:\) は "__root__" へ戻せるようにする
            yield return new FileSelectorItem
            {
                DisplayName = "..",
                FullPath = parent != null ? parent.FullName : "__root__",
                IsDir = true,
                Size = 0,
                IsUpEntry = true,     // ← 追加
            };
        }
        IEnumerable<string> dirs = Array.Empty<string>();
        try { dirs = Directory.EnumerateDirectories(dir); } catch { /* アクセス不可などは無視 */ }

        foreach (var d in dirs)
        {
            var di = new DirectoryInfo(d);
            if ((di.Attributes & FileAttributes.Hidden) == FileAttributes.Hidden) continue;
            if ((di.Attributes & FileAttributes.System) == FileAttributes.System) continue;

            yield return new FileSelectorItem
            {
                DisplayName = di.Name,
                FullPath = di.FullName,
                IsDir = true,
                Size = 0,
            };
        }

        IEnumerable<string> files = Array.Empty<string>();
        try { files = Directory.EnumerateFiles(dir); } catch { }

        foreach (var f in files)
        {
            var fi = new FileInfo(f);
            if ((fi.Attributes & FileAttributes.Hidden) == FileAttributes.Hidden) continue;
            if ((fi.Attributes & FileAttributes.System) == FileAttributes.System) continue;

            yield return new FileSelectorItem
            {
                DisplayName = fi.Name,
                FullPath = fi.FullName,
                IsDir = false,
                Size = fi.Length,
            };
        }
    }
}

namespace FileSelector02;
public interface IFileSystemService
{
    IEnumerable<FileSelectorItem> Enumerate(string directoryPath);
}

using System.Globalization;
using System.Windows.Data;

public sealed class ByteSizeConverter : IValueConverter
{
    // parameter 例:
    //  "KB"      … KB固定（少数0桁）
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (value is not long bytes) return "";
        if (bytes < 0) bytes = 0; // 念のため

        double size = bytes;

        size = bytes / 1024.0;

        string format = "N0";
        return $"{size.ToString(format, culture)} KB";
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        => throw new NotSupportedException();
}

using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Media;

namespace FileSelector02;

public class FileSelector : ListView
{
    private static readonly IValueConverter ByteSizeConv = new ByteSizeConverter();

    public FileSelector()
    {
        // ItemsSource: ICollectionView
        SetBinding(ItemsControl.ItemsSourceProperty, new Binding(nameof(FileSelectorViewModel.View)));

        // 行の水平ストレッチ
        var style = new Style(typeof(ListViewItem));
        style.Setters.Add(new Setter(ListViewItem.HorizontalContentAlignmentProperty, HorizontalAlignment.Stretch));
        ItemContainerStyle = style;

        // Name列テンプレート（アイコン+名前）
        var nameTemplate = new DataTemplate();
        var nameStack = new FrameworkElementFactory(typeof(StackPanel));
        nameStack.SetValue(StackPanel.OrientationProperty, Orientation.Horizontal);

        // ① アイコン TextBlock（デフォルトはファイル📄）
        var iconTb = new FrameworkElementFactory(typeof(TextBlock));
        iconTb.Name = "Icon";
        iconTb.SetValue(TextBlock.TextProperty, "📄");
        iconTb.SetValue(TextBlock.FontSizeProperty, 12.0);
        iconTb.SetValue(FrameworkElement.MarginProperty, new Thickness(0, 0, 6, 0));
        nameStack.AppendChild(iconTb);

        // ② 名前 TextBlock
        var textTb = new FrameworkElementFactory(typeof(TextBlock));
        textTb.SetBinding(TextBlock.TextProperty, new Binding(nameof(FileSelectorItem.DisplayName)));
        nameStack.AppendChild(textTb);

        nameTemplate.VisualTree = nameStack;

        // ③ DataTriggerで上書き
        // UpEntry（..）は ⬆ を表示
        var upTrig = new DataTrigger { Binding = new Binding(nameof(FileSelectorItem.IsUpEntry)), Value = true };
        upTrig.Setters.Add(new Setter(TextBlock.TextProperty, "⬆", targetName: "Icon"));
        nameTemplate.Triggers.Add(upTrig);

        // ディレクトリは 📁 を表示（UpEntryより後に効かせたい場合は順序を入れ替えてください）
        var dirTrig = new DataTrigger { Binding = new Binding(nameof(FileSelectorItem.IsDir)), Value = true };
        dirTrig.Setters.Add(new Setter(TextBlock.TextProperty, "📁", targetName: "Icon"));
        nameTemplate.Triggers.Add(dirTrig);

        // Size列テンプレート（右寄せ、ディレクトリ非表示）
        var sizeTemplate = new DataTemplate();
        var sizeTB = new FrameworkElementFactory(typeof(TextBlock));
        sizeTB.Name = "SizeTB";
        sizeTB.SetBinding(TextBlock.TextProperty, new Binding(nameof(FileSelectorItem.Size)) { Converter = ByteSizeConv });
        sizeTB.SetValue(TextBlock.HorizontalAlignmentProperty, HorizontalAlignment.Right);
        sizeTemplate.VisualTree = sizeTB;
        var hideDir = new DataTrigger { Binding = new Binding(nameof(FileSelectorItem.IsDir)), Value = true };
        hideDir.Setters.Add(new Setter(UIElement.VisibilityProperty, Visibility.Collapsed, "SizeTB"));
        sizeTemplate.Triggers.Add(hideDir);

        // GridView 構築（ヘッダーは Button→SortByCommand）
        var gv = new GridView();

        gv.Columns.Add(new GridViewColumn
        {
            Header = MakeHeaderButton("Name", nameof(FileSelectorItem.DisplayName)),
            CellTemplate = nameTemplate,
            Width = 140
        });

        gv.Columns.Add(new GridViewColumn
        {
            Header = MakeHeaderButton("Size", nameof(FileSelectorItem.Size)),
            CellTemplate = sizeTemplate,
            Width = 60
        });

        View = gv;

        // 選択バインド
        SetBinding(SelectedItemProperty, new Binding(nameof(FileSelectorViewModel.SelectedItem)) { Mode = BindingMode.TwoWay });

        // ダブルクリックでフォルダ移動
        MouseDoubleClick += (_, __) =>
        {
            if (DataContext is FileSelectorViewModel vm && vm.OpenSelectedCommand.CanExecute(null))
                vm.OpenSelectedCommand.Execute(null);
        };
    }

    private static Button MakeHeaderButton(string text, string propertyName)
    {
        var btn = new Button
        {
            Content = text,
            Padding = new Thickness(4, 0, 4, 0),
            Background = Brushes.Transparent,
            BorderBrush = Brushes.Transparent
        };

        // マウスオーバー時の背景変更を抑制
        btn.Focusable = false;

        // コマンドバインド
        btn.SetBinding(Button.CommandProperty, new Binding(nameof(FileSelectorViewModel.SortByCommand)));
        btn.CommandParameter = propertyName switch
        {
            nameof(FileSelectorItem.DisplayName) => "Name",
            _ => propertyName
        };

        return btn;
    }
}

using System.Windows;
using System.Windows.Controls;

namespace FileSelector02;

public class MainWindow : Window
{
    public MainWindow()
    {
        Title = "NoXAML FileSelector";
        Width = 400;
        Height = 300;

        var vm = new MainWindowViewModel();
        DataContext = vm;

        var root = new DockPanel();
        var fileSelector = new FileSelector { DataContext = vm.FileSelectorVM };
        root.Children.Add(fileSelector);
        Content = root;
    }
}

using System.ComponentModel;
using System.Windows.Data;
using System.Windows.Input;

namespace FileSelector02;

public class FileSelectorViewModel : SelectorViewModel<FileSelectorItem>
{
    private readonly IFileSystemService _fs;

    private string _currentDirectory;
    public string CurrentDirectory
    {
        get => _currentDirectory;
        set
        {
            if (_currentDirectory == value) return;
            _currentDirectory = value;
            OnPropertyChanged();
            Refresh();
        }
    }

    public ICommand OpenSelectedCommand { get; }

    public FileSelectorViewModel(IFileSystemService fs, string initialDir)
    {
        _fs = fs;
        _currentDirectory = initialDir;

        // 既定の固定キー: 「..」最上位 → ディレクトリ先頭
        using (View.DeferRefresh())
        {
            View.SortDescriptions.Clear();
            View.SortDescriptions.Add(new SortDescription(nameof(FileSelectorItem.IsUpEntry), ListSortDirection.Descending));
            View.SortDescriptions.Add(new SortDescription(nameof(FileSelectorItem.IsDir),     ListSortDirection.Descending));
            View.SortDescriptions.Add(new SortDescription(nameof(FileSelectorItem.DisplayName), ListSortDirection.Ascending));
            _lastSortProperty = nameof(FileSelectorItem.DisplayName);
            _lastDirection = ListSortDirection.Ascending;
        }

        OpenSelectedCommand = new RelayCommand(_ =>
        {
            var item = SelectedItem;
            if (item is null) return;
            if (item.IsDir) CurrentDirectory = item.FullPath;
            // else: 必要ならファイル起動処理をここに
        }, _ => SelectedItem is not null);

        Refresh();
    }

    public void Refresh()
    {
        Items.Clear();
        foreach (var x in _fs.Enumerate(CurrentDirectory))
            Items.Add(x);
    }

    // 列クリックでのトグル（固定キーは保持しつつ、クリック列を差し替え）
    protected override void ApplySort(string property, ListSortDirection direction)
    {
        // 見出し名 → 実プロパティ名解決
        property = property switch
        {
            "Name" => nameof(FileSelectorItem.DisplayName),
            "Size" => nameof(FileSelectorItem.Size),
            _ => property
        };

        using (View.DeferRefresh())
        {
            View.SortDescriptions.Clear();
            View.SortDescriptions.Add(new SortDescription(nameof(FileSelectorItem.IsUpEntry), ListSortDirection.Descending));
            View.SortDescriptions.Add(new SortDescription(nameof(FileSelectorItem.IsDir),     ListSortDirection.Descending));
            View.SortDescriptions.Add(new SortDescription(property, direction));
            if (property != nameof(FileSelectorItem.DisplayName))
                View.SortDescriptions.Add(new SortDescription(nameof(FileSelectorItem.DisplayName), ListSortDirection.Ascending));
        }
        _lastSortProperty = property;
        _lastDirection = direction;
    }
}

namespace FileSelector02;

public class MainWindowViewModel
{
    public FileSelectorViewModel FileSelectorVM { get; }
    public MainWindowViewModel()
    {
        var fs = new FileSystemService();
        FileSelectorVM = new(fs, Environment.GetFolderPath(Environment.SpecialFolder.UserProfile));
    }
}

using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Windows.Data;

namespace FileSelector02;

public class SelectorViewModel<T> : ObservableObject
{
    public ObservableCollection<T> Items { get; } = [];
    public ICollectionView View { get; }

    private T? _selectedItem;
    public T? SelectedItem
    {
        get => _selectedItem;
        set => Set(ref _selectedItem, value);
    }

    public RelayCommand SortByCommand { get; }
    public RelayCommand ClearSortCommand { get; }
    public RelayCommand SetFilterCommand { get; }

    protected string? _lastSortProperty;
    protected ListSortDirection _lastDirection = ListSortDirection.Ascending;

    private Predicate<object?>? _filter;
    public Predicate<object?>? Filter
    {
        get => _filter;
        set { _filter = value; View.Refresh(); }
    }

    public SelectorViewModel()
    {
        View = CollectionViewSource.GetDefaultView(Items);
        View.Filter = o => _filter?.Invoke(o) ?? true;

        SortByCommand = new RelayCommand(p =>
        {
            var prop = p as string;
            if (string.IsNullOrWhiteSpace(prop)) return;

            var dir = _lastSortProperty == prop
                ? (_lastDirection == ListSortDirection.Ascending ? ListSortDirection.Descending : ListSortDirection.Ascending)
                : ListSortDirection.Ascending;

            ApplySort(prop, dir);
        });

        ClearSortCommand = new RelayCommand(_ =>
        {
            using (View.DeferRefresh()) View.SortDescriptions.Clear();
            _lastSortProperty = null;
        });

        SetFilterCommand = new RelayCommand(qobj =>
        {
            var q = (qobj as string)?.Trim();
            Filter = string.IsNullOrEmpty(q)
                ? null
                : (o => o?.ToString()?.Contains(q, System.StringComparison.OrdinalIgnoreCase) == true);
        });
    }

    protected virtual void ApplySort(string property, ListSortDirection direction)
    {
        using (View.DeferRefresh())
        {
            View.SortDescriptions.Clear();
            // ここでは「汎用」なので、派生で固定キーを差し込むことを想定
            View.SortDescriptions.Add(new SortDescription(property, direction));
        }
        _lastSortProperty = property;
        _lastDirection = direction;
    }
}