C#のWPFでドライブの一覧とカレントディレクトリの階層を選択するコンボボックスを作る。

<Window x:Class="SelectDriveCombo.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:i="clr-namespace:Microsoft.Xaml.Behaviors;assembly=Microsoft.Xaml.Behaviors"
        xmlns:interactivity="clr-namespace:Reactive.Bindings.Interactivity;assembly=ReactiveProperty.WPF"
        xmlns:local="clr-namespace:SelectDriveCombo"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Window.DataContext>
        <local:MainWindowViewModel />
    </Window.DataContext>
    <i:Interaction.Triggers>
        <i:EventTrigger EventName="Closed">
            <interactivity:EventToReactiveCommand Command="{Binding WindowClosedCommand}" />
        </i:EventTrigger>
    </i:Interaction.Triggers>
    <Grid>
        <StackPanel>
            <ComboBox
                SelectedValuePath="FullPath"
                SelectedValue="{Binding DrivesSelected.Value}"
                ItemsSource="{Binding Drives}">
                <ComboBox.ItemTemplate>
                    <DataTemplate>
                        <StackPanel
                            Orientation="Horizontal">
                            <Image Margin="{Binding Margin}" Source="{Binding IconPath}" />
                            <TextBlock Margin="4,0,0,0" Text="{Binding Name}"></TextBlock>
                        </StackPanel>
                    </DataTemplate>
                </ComboBox.ItemTemplate>
            </ComboBox>
        </StackPanel>
    </Grid>
</Window>

using System;
using System.ComponentModel;
using Reactive.Bindings;
using Reactive.Bindings.Extensions;
using System.Reactive.Disposables;

using System.Diagnostics;
using System.Data.Common;
using System.IO;
using System.Runtime.CompilerServices;

using System.Drawing;
using System.Windows.Media.Imaging;

namespace SelectDriveCombo;

public class MainWindowViewModel : INotifyPropertyChanged, IDisposable
{
    public event PropertyChangedEventHandler? PropertyChanged;
    protected virtual void OnPropertyChanged(string name)
    {
        if (PropertyChanged is not null)
            PropertyChanged(this, new PropertyChangedEventArgs(name));
    }
    private CompositeDisposable Disposable { get; } = new ();
    public void Dispose() => Disposable.Dispose();
    public ReactiveCommand<EventArgs> WindowClosedCommand { get; }
    
    public ReactiveProperty<string> DrivesSelected { get; set; } = new("");
    public ReactiveCollection<DriveEntity> Drives { get; set; } = new();

    public MainWindowViewModel()
    {
        WindowClosedCommand = new ReactiveCommand<EventArgs>()
            .WithSubscribe(e => Disposable.Dispose());

        // カレントディレクトリを取得
        var carrentDir = Directory.GetCurrentDirectory();
        // カレントドライブを取得
        var carrentDrive = Path.GetPathRoot(carrentDir) ?? "";
        // クリア
        Drives.ClearOnScheduler();
        // ドライブの一覧を取得
        foreach(var drive in Directory.GetLogicalDrives())
        {
            // 追加
            Drives.AddOnScheduler
            (
                new DriveEntity{ Name = drive, FullPath = drive, IconPath = @"H:\csharp\dotnet8\wpf\SelectDriveCombo\drive.png"  }
            );
            if (drive.Equals(carrentDrive, StringComparison.CurrentCultureIgnoreCase))
            {
                string tmp = carrentDir;
                Stack<string> tmps = new();
                while(!carrentDrive.Equals(tmp, StringComparison.CurrentCultureIgnoreCase))
                {
                    tmps.Push(tmp);
                    tmp = Path.GetDirectoryName(tmp) ?? carrentDrive;
                }
                int i = 1;
                foreach(var t in tmps)
                {
                    string name = Path.GetFileName(t);
                    Drives.AddOnScheduler
                    (
                        new DriveEntity{ Name = name, FullPath = t, MarginLeft = (i * 10),  IconPath = @"H:\csharp\dotnet8\wpf\SelectDriveCombo\folder.png" }
                    );
                    i++;
                }
            }
        }
        // 選択されたドライブを表示
        DrivesSelected.Subscribe(e=>
        {
            Debug.Print(DrivesSelected.Value);
        });
    }
}

public class DriveEntity
{
    public string Name { get; set; } = "";
    public string FullPath { get; set; } = "";
    public string IconPath { get; set; } = "";
    public int MarginLeft { get; set; } = 0;

    public string Margin { get { return $"{MarginLeft},0,0,0"; } }
}