feat(13-02): add directory browse mode with paginated load, member/guest filter, and sortable ICollectionView

- Inject IGraphUserDirectoryService into UserAccessAuditViewModel (both constructors)
- Add IsBrowseMode toggle, DirectoryUsers collection, DirectoryUsersView with sort/filter
- Add LoadDirectoryCommand with progress reporting, cancellation, and error handling
- Add IncludeGuests toggle for in-memory member/guest filtering (no new Graph request)
- Add DirectoryFilterText for DisplayName/UPN/Department/JobTitle text search
- Add DirectoryUserCount computed property reflecting filtered view count
- Update OnTenantSwitched to clear all directory state
- Add 16 comprehensive unit tests covering all directory browse behaviors

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

SharepointToolbox.Tests/ViewModels/UserAccessAuditViewModelDirectoryTests.cs

@@ -0,0 +1,351 @@
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using CommunityToolkit.Mvvm.Messaging;
+using Microsoft.Extensions.Logging.Abstractions;
+using Moq;
+using SharepointToolbox.Core.Models;
+using SharepointToolbox.Services;
+using SharepointToolbox.ViewModels;
+using SharepointToolbox.ViewModels.Tabs;
+
+namespace SharepointToolbox.Tests.ViewModels;
+
+/// <summary>
+/// Unit tests for directory browse mode in UserAccessAuditViewModel (Phase 13 Plan 02).
+/// Verifies: directory load, progress, cancellation, member/guest filter, text filter,
+/// sorting, tenant switch reset, and no regression on search mode.
+/// </summary>
+[Trait("Category", "Unit")]
+public class UserAccessAuditViewModelDirectoryTests
+{
+    public UserAccessAuditViewModelDirectoryTests()
+    {
+        WeakReferenceMessenger.Default.Reset();
+    }
+
+    // ── Helper factories ──────────────────────────────────────────────────────
+
+    private static GraphDirectoryUser MakeMember(string name = "Alice", string dept = "IT", string jobTitle = "Engineer") =>
+        new(name, $"{name.ToLower().Replace(" ", "")}@contoso.com", null, dept, jobTitle, "Member");
+
+    private static GraphDirectoryUser MakeGuest(string name = "Bob External") =>
+        new(name, $"{name.ToLower().Replace(" ", "")}@external.com", null, null, null, "Guest");
+
+    private static (UserAccessAuditViewModel vm, Mock<IGraphUserDirectoryService> dirMock, Mock<IUserAccessAuditService> auditMock)
+        CreateViewModel(IReadOnlyList<GraphDirectoryUser>? directoryResult = null)
+    {
+        var mockAudit = new Mock<IUserAccessAuditService>();
+        var mockGraph = new Mock<IGraphUserSearchService>();
+        var mockSession = new Mock<ISessionManager>();
+        var mockDir = new Mock<IGraphUserDirectoryService>();
+        mockDir.Setup(s => s.GetUsersAsync(
+                It.IsAny<string>(),
+                It.IsAny<bool>(),
+                It.IsAny<IProgress<int>>(),
+                It.IsAny<CancellationToken>()))
+            .ReturnsAsync(directoryResult ?? Array.Empty<GraphDirectoryUser>());
+
+        var vm = new UserAccessAuditViewModel(
+            mockAudit.Object,
+            mockGraph.Object,
+            mockSession.Object,
+            NullLogger<FeatureViewModelBase>.Instance,
+            graphUserDirectoryService: mockDir.Object);
+
+        vm._currentProfile = new TenantProfile
+        {
+            Name = "Test",
+            TenantUrl = "https://contoso.sharepoint.com",
+            ClientId = "test-client-id"
+        };
+
+        return (vm, mockDir, mockAudit);
+    }
+
+    // ── Test 1: IsBrowseMode defaults to false ───────────────────────────────
+
+    [Fact]
+    public void IsBrowseMode_defaults_to_false()
+    {
+        var (vm, _, _) = CreateViewModel();
+        Assert.False(vm.IsBrowseMode);
+    }
+
+    // ── Test 2: DirectoryUsers is empty by default ───────────────────────────
+
+    [Fact]
+    public void DirectoryUsers_empty_by_default()
+    {
+        var (vm, _, _) = CreateViewModel();
+        Assert.Empty(vm.DirectoryUsers);
+    }
+
+    // ── Test 3: Commands are not null ─────────────────────────────────────────
+
+    [Fact]
+    public void LoadDirectoryCommand_and_CancelDirectoryLoadCommand_not_null()
+    {
+        var (vm, _, _) = CreateViewModel();
+        Assert.NotNull(vm.LoadDirectoryCommand);
+        Assert.NotNull(vm.CancelDirectoryLoadCommand);
+    }
+
+    // ── Test 4: LoadDirectoryAsync populates DirectoryUsers ──────────────────
+
+    [Fact]
+    public async Task LoadDirectoryAsync_populates_DirectoryUsers()
+    {
+        var users = new List<GraphDirectoryUser> { MakeMember("Alice"), MakeMember("Charlie") };
+        var (vm, _, _) = CreateViewModel(users);
+
+        await vm.TestLoadDirectoryAsync();
+
+        Assert.Equal(2, vm.DirectoryUsers.Count);
+        Assert.Contains(vm.DirectoryUsers, u => u.DisplayName == "Alice");
+        Assert.Contains(vm.DirectoryUsers, u => u.DisplayName == "Charlie");
+    }
+
+    // ── Test 5: LoadDirectoryAsync reports progress via DirectoryLoadStatus ──
+
+    [Fact]
+    public async Task LoadDirectoryAsync_sets_DirectoryLoadStatus_on_completion()
+    {
+        var users = new List<GraphDirectoryUser> { MakeMember("Alice") };
+        var (vm, _, _) = CreateViewModel(users);
+
+        await vm.TestLoadDirectoryAsync();
+
+        Assert.Equal("1 users loaded", vm.DirectoryLoadStatus);
+    }
+
+    // ── Test 6: LoadDirectoryAsync with no profile sets StatusMessage ─────────
+
+    [Fact]
+    public async Task LoadDirectoryAsync_with_no_profile_sets_StatusMessage()
+    {
+        var (vm, _, _) = CreateViewModel();
+        vm._currentProfile = null;
+
+        await vm.TestLoadDirectoryAsync();
+
+        Assert.Equal("No tenant profile selected. Please connect first.", vm.StatusMessage);
+        Assert.Empty(vm.DirectoryUsers);
+    }
+
+    // ── Test 7: CancelDirectoryLoadCommand cancels in-flight load ────────────
+
+    [Fact]
+    public async Task CancelDirectoryLoad_cancels_inflight_load()
+    {
+        var tcs = new TaskCompletionSource<IReadOnlyList<GraphDirectoryUser>>();
+        var mockDir = new Mock<IGraphUserDirectoryService>();
+        mockDir.Setup(s => s.GetUsersAsync(
+                It.IsAny<string>(),
+                It.IsAny<bool>(),
+                It.IsAny<IProgress<int>>(),
+                It.IsAny<CancellationToken>()))
+            .Returns<string, bool, IProgress<int>?, CancellationToken>((_, _, _, ct) =>
+            {
+                var localTcs = new TaskCompletionSource<IReadOnlyList<GraphDirectoryUser>>();
+                ct.Register(() => localTcs.TrySetCanceled(ct));
+                return localTcs.Task;
+            });
+
+        var vm = new UserAccessAuditViewModel(
+            new Mock<IUserAccessAuditService>().Object,
+            new Mock<IGraphUserSearchService>().Object,
+            new Mock<ISessionManager>().Object,
+            NullLogger<FeatureViewModelBase>.Instance,
+            graphUserDirectoryService: mockDir.Object);
+        vm._currentProfile = new TenantProfile
+        {
+            Name = "Test",
+            TenantUrl = "https://contoso.sharepoint.com",
+            ClientId = "test-client-id"
+        };
+
+        // Start load (will block on the mock)
+        var loadTask = vm.TestLoadDirectoryAsync();
+
+        // Cancel
+        vm.CancelDirectoryLoadCommand.Execute(null);
+
+        await loadTask;
+
+        Assert.Equal("Load cancelled.", vm.DirectoryLoadStatus);
+        Assert.False(vm.IsLoadingDirectory);
+    }
+
+    // ── Test 8: IncludeGuests=false filters out Guest users ──────────────────
+
+    [Fact]
+    public void IncludeGuests_false_filters_out_guest_users()
+    {
+        var (vm, _, _) = CreateViewModel();
+        vm.DirectoryUsers.Add(MakeMember("Alice"));
+        vm.DirectoryUsers.Add(MakeGuest("Bob External"));
+        vm.DirectoryUsers.Add(MakeMember("Charlie"));
+
+        vm.IncludeGuests = false;
+
+        var visible = vm.DirectoryUsersView.Cast<GraphDirectoryUser>().ToList();
+        Assert.Equal(2, visible.Count);
+        Assert.All(visible, u => Assert.Equal("Member", u.UserType));
+    }
+
+    // ── Test 9: IncludeGuests=true shows all users ───────────────────────────
+
+    [Fact]
+    public void IncludeGuests_true_shows_all_users()
+    {
+        var (vm, _, _) = CreateViewModel();
+        vm.DirectoryUsers.Add(MakeMember("Alice"));
+        vm.DirectoryUsers.Add(MakeGuest("Bob External"));
+
+        vm.IncludeGuests = true;
+
+        var visible = vm.DirectoryUsersView.Cast<GraphDirectoryUser>().ToList();
+        Assert.Equal(2, visible.Count);
+    }
+
+    // ── Test 10: DirectoryFilterText filters by DisplayName ──────────────────
+
+    [Fact]
+    public void DirectoryFilterText_filters_by_DisplayName()
+    {
+        var (vm, _, _) = CreateViewModel();
+        vm.DirectoryUsers.Add(MakeMember("Alice"));
+        vm.DirectoryUsers.Add(MakeMember("Charlie"));
+        vm.IncludeGuests = true;
+
+        vm.DirectoryFilterText = "Ali";
+
+        var visible = vm.DirectoryUsersView.Cast<GraphDirectoryUser>().ToList();
+        Assert.Single(visible);
+        Assert.Equal("Alice", visible[0].DisplayName);
+    }
+
+    // ── Test 11: DirectoryFilterText filters by Department ───────────────────
+
+    [Fact]
+    public void DirectoryFilterText_filters_by_Department()
+    {
+        var (vm, _, _) = CreateViewModel();
+        vm.DirectoryUsers.Add(MakeMember("Alice", dept: "Engineering"));
+        vm.DirectoryUsers.Add(MakeMember("Charlie", dept: "Marketing"));
+        vm.IncludeGuests = true;
+
+        vm.DirectoryFilterText = "Market";
+
+        var visible = vm.DirectoryUsersView.Cast<GraphDirectoryUser>().ToList();
+        Assert.Single(visible);
+        Assert.Equal("Charlie", visible[0].DisplayName);
+    }
+
+    // ── Test 12: DirectoryUsersView default sort is DisplayName ascending ────
+
+    [Fact]
+    public void DirectoryUsersView_sorted_by_DisplayName_ascending()
+    {
+        var (vm, _, _) = CreateViewModel();
+        vm.DirectoryUsers.Add(MakeMember("Charlie"));
+        vm.DirectoryUsers.Add(MakeMember("Alice"));
+        vm.DirectoryUsers.Add(MakeMember("Bob"));
+        vm.IncludeGuests = true;
+
+        var visible = vm.DirectoryUsersView.Cast<GraphDirectoryUser>().ToList();
+        Assert.Equal("Alice", visible[0].DisplayName);
+        Assert.Equal("Bob", visible[1].DisplayName);
+        Assert.Equal("Charlie", visible[2].DisplayName);
+    }
+
+    // ── Test 13: OnTenantSwitched clears directory state ─────────────────────
+
+    [Fact]
+    public async Task OnTenantSwitched_clears_directory_state()
+    {
+        var users = new List<GraphDirectoryUser> { MakeMember("Alice") };
+        var (vm, _, _) = CreateViewModel(users);
+
+        // Load directory
+        await vm.TestLoadDirectoryAsync();
+        Assert.NotEmpty(vm.DirectoryUsers);
+        vm.IsBrowseMode = true;
+        vm.DirectoryFilterText = "test";
+        vm.IncludeGuests = true;
+
+        // Act: switch tenant
+        var newProfile = new TenantProfile
+        {
+            Name = "NewTenant",
+            TenantUrl = "https://newtenant.sharepoint.com",
+            ClientId = "new-client-id"
+        };
+        WeakReferenceMessenger.Default.Send(new Core.Messages.TenantSwitchedMessage(newProfile));
+
+        // Assert
+        Assert.Empty(vm.DirectoryUsers);
+        Assert.False(vm.IsBrowseMode);
+        Assert.Empty(vm.DirectoryFilterText);
+        Assert.Empty(vm.DirectoryLoadStatus);
+        Assert.False(vm.IsLoadingDirectory);
+        Assert.False(vm.IncludeGuests);
+    }
+
+    // ── Test 14: DirectoryUserCount reflects filtered count ───────────────────
+
+    [Fact]
+    public void DirectoryUserCount_reflects_filtered_count()
+    {
+        var (vm, _, _) = CreateViewModel();
+        vm.DirectoryUsers.Add(MakeMember("Alice"));
+        vm.DirectoryUsers.Add(MakeGuest("Bob External"));
+        vm.DirectoryUsers.Add(MakeMember("Charlie"));
+
+        // With guests hidden (default IncludeGuests=false)
+        vm.IncludeGuests = false;
+        Assert.Equal(2, vm.DirectoryUserCount);
+
+        // With guests shown
+        vm.IncludeGuests = true;
+        Assert.Equal(3, vm.DirectoryUserCount);
+
+        // With text filter
+        vm.DirectoryFilterText = "Ali";
+        Assert.Equal(1, vm.DirectoryUserCount);
+    }
+
+    // ── Test 15: Search mode still works (no regression) ─────────────────────
+
+    [Fact]
+    public void Search_mode_SelectedUsers_still_works()
+    {
+        var (vm, _, _) = CreateViewModel();
+
+        // Search mode properties should be functional
+        Assert.Empty(vm.SelectedUsers);
+        vm.SelectedUsers.Add(new GraphUserResult("Alice Smith", "alice@contoso.com", "alice@contoso.com"));
+        Assert.Single(vm.SelectedUsers);
+        Assert.Equal("1 user(s) selected", vm.SelectedUsersLabel);
+    }
+
+    // ── Test 16: DirectoryFilterText filters by JobTitle ─────────────────────
+
+    [Fact]
+    public void DirectoryFilterText_filters_by_JobTitle()
+    {
+        var (vm, _, _) = CreateViewModel();
+        vm.DirectoryUsers.Add(MakeMember("Alice", jobTitle: "Senior Developer"));
+        vm.DirectoryUsers.Add(MakeMember("Charlie", jobTitle: "Product Manager"));
+        vm.IncludeGuests = true;
+
+        vm.DirectoryFilterText = "Developer";
+
+        var visible = vm.DirectoryUsersView.Cast<GraphDirectoryUser>().ToList();
+        Assert.Single(visible);
+        Assert.Equal("Alice", visible[0].DisplayName);
+    }
+}

SharepointToolbox/ViewModels/Tabs/UserAccessAuditViewModel.cs

@@ -26,6 +26,7 @@ public partial class UserAccessAuditViewModel : FeatureViewModelBase
     private readonly UserAccessCsvExportService? _csvExportService;
     private readonly UserAccessHtmlExportService? _htmlExportService;
     private readonly IBrandingService? _brandingService;
+    private readonly IGraphUserDirectoryService? _graphUserDirectoryService;
     private readonly ILogger<FeatureViewModelBase> _logger;
 
     // ── People picker debounce ──────────────────────────────────────────────
@@ -74,6 +75,34 @@ public partial class UserAccessAuditViewModel : FeatureViewModelBase
     [ObservableProperty]
     private bool _isSearching;
 
+    // ── Directory browse mode properties ───────────────────────────────────
+
+    /// <summary>When true, the UI shows the directory browse panel instead of the people-picker search.</summary>
+    [ObservableProperty]
+    private bool _isBrowseMode;
+
+    /// <summary>All directory users loaded from Graph.</summary>
+    [ObservableProperty]
+    private ObservableCollection<GraphDirectoryUser> _directoryUsers = new();
+
+    /// <summary>True while a directory load is in progress.</summary>
+    [ObservableProperty]
+    private bool _isLoadingDirectory;
+
+    /// <summary>Status text for directory load progress, e.g. "Loading... 500 users".</summary>
+    [ObservableProperty]
+    private string _directoryLoadStatus = string.Empty;
+
+    /// <summary>When true, guest users are shown in the directory view; when false, only members.</summary>
+    [ObservableProperty]
+    private bool _includeGuests;
+
+    /// <summary>Text filter applied to DirectoryUsersView (DisplayName, UPN, Department, JobTitle).</summary>
+    [ObservableProperty]
+    private string _directoryFilterText = string.Empty;
+
+    private CancellationTokenSource? _directoryCts = null;
+
     // ── Computed summary properties ─────────────────────────────────────────
 
     /// <summary>Total number of access entries in current results.</summary>
@@ -91,17 +120,25 @@ public partial class UserAccessAuditViewModel : FeatureViewModelBase
             ? $"{SelectedUsers.Count} user(s) selected"
             : string.Empty;
 
+    /// <summary>Number of users currently visible in the filtered directory view.</summary>
+    public int DirectoryUserCount => DirectoryUsersView?.Cast<object>().Count() ?? 0;
+
     // ── CollectionViewSource (grouping + filtering) ─────────────────────────
 
     /// <summary>ICollectionView over Results supporting grouping and text filtering.</summary>
     public ICollectionView ResultsView { get; }
 
+    /// <summary>ICollectionView over DirectoryUsers with member/guest and text filtering, sorted by DisplayName.</summary>
+    public ICollectionView DirectoryUsersView { get; }
+
     // ── Commands ────────────────────────────────────────────────────────────
 
     public IAsyncRelayCommand ExportCsvCommand { get; }
     public IAsyncRelayCommand ExportHtmlCommand { get; }
     public RelayCommand<GraphUserResult> AddUserCommand { get; }
     public RelayCommand<GraphUserResult> RemoveUserCommand { get; }
+    public IAsyncRelayCommand LoadDirectoryCommand { get; }
+    public RelayCommand CancelDirectoryLoadCommand { get; }
 
     // ── Current tenant profile ──────────────────────────────────────────────
 
@@ -120,6 +157,7 @@ public partial class UserAccessAuditViewModel : FeatureViewModelBase
         UserAccessCsvExportService csvExportService,
         UserAccessHtmlExportService htmlExportService,
         IBrandingService brandingService,
+        IGraphUserDirectoryService graphUserDirectoryService,
         ILogger<FeatureViewModelBase> logger)
         : base(logger)
     {
@@ -129,6 +167,7 @@ public partial class UserAccessAuditViewModel : FeatureViewModelBase
         _csvExportService = csvExportService;
         _htmlExportService = htmlExportService;
         _brandingService = brandingService;
+        _graphUserDirectoryService = graphUserDirectoryService;
         _logger = logger;
 
         ExportCsvCommand = new AsyncRelayCommand(ExportCsvAsync, CanExport);
@@ -141,6 +180,17 @@ public partial class UserAccessAuditViewModel : FeatureViewModelBase
         var cvs = new CollectionViewSource { Source = Results };
         ResultsView = cvs.View;
         ApplyGrouping();
+
+        var dirCvs = new CollectionViewSource { Source = DirectoryUsers };
+        DirectoryUsersView = dirCvs.View;
+        DirectoryUsersView.SortDescriptions.Add(
+            new SortDescription(nameof(GraphDirectoryUser.DisplayName), ListSortDirection.Ascending));
+        DirectoryUsersView.Filter = DirectoryFilterPredicate;
+
+        LoadDirectoryCommand = new AsyncRelayCommand(LoadDirectoryAsync, () => !IsLoadingDirectory);
+        CancelDirectoryLoadCommand = new RelayCommand(
+            () => _directoryCts?.Cancel(),
+            () => IsLoadingDirectory);
     }
 
     /// <summary>Test constructor — omits export services (not needed for unit tests).</summary>
@@ -149,7 +199,8 @@ public partial class UserAccessAuditViewModel : FeatureViewModelBase
         IGraphUserSearchService graphUserSearchService,
         ISessionManager sessionManager,
         ILogger<FeatureViewModelBase> logger,
-        IBrandingService? brandingService = null)
+        IBrandingService? brandingService = null,
+        IGraphUserDirectoryService? graphUserDirectoryService = null)
         : base(logger)
     {
         _auditService = auditService;
@@ -158,6 +209,7 @@ public partial class UserAccessAuditViewModel : FeatureViewModelBase
         _csvExportService = null;
         _htmlExportService = null;
         _brandingService = brandingService;
+        _graphUserDirectoryService = graphUserDirectoryService;
         _logger = logger;
 
         ExportCsvCommand = new AsyncRelayCommand(ExportCsvAsync, CanExport);
@@ -170,6 +222,17 @@ public partial class UserAccessAuditViewModel : FeatureViewModelBase
         var cvs = new CollectionViewSource { Source = Results };
         ResultsView = cvs.View;
         ApplyGrouping();
+
+        var dirCvs = new CollectionViewSource { Source = DirectoryUsers };
+        DirectoryUsersView = dirCvs.View;
+        DirectoryUsersView.SortDescriptions.Add(
+            new SortDescription(nameof(GraphDirectoryUser.DisplayName), ListSortDirection.Ascending));
+        DirectoryUsersView.Filter = DirectoryFilterPredicate;
+
+        LoadDirectoryCommand = new AsyncRelayCommand(LoadDirectoryAsync, () => !IsLoadingDirectory);
+        CancelDirectoryLoadCommand = new RelayCommand(
+            () => _directoryCts?.Cancel(),
+            () => IsLoadingDirectory);
     }
 
     // ── FeatureViewModelBase implementation ─────────────────────────────────
@@ -251,6 +314,18 @@ public partial class UserAccessAuditViewModel : FeatureViewModelBase
         NotifySummaryProperties();
         ExportCsvCommand.NotifyCanExecuteChanged();
         ExportHtmlCommand.NotifyCanExecuteChanged();
+
+        // Directory browse mode reset
+        _directoryCts?.Cancel();
+        _directoryCts?.Dispose();
+        _directoryCts = null;
+        DirectoryUsers.Clear();
+        DirectoryFilterText = string.Empty;
+        DirectoryLoadStatus = string.Empty;
+        IsBrowseMode = false;
+        IsLoadingDirectory = false;
+        IncludeGuests = false;
+        OnPropertyChanged(nameof(DirectoryUserCount));
     }
 
     // ── Observable property change handlers ─────────────────────────────────
@@ -285,6 +360,24 @@ public partial class UserAccessAuditViewModel : FeatureViewModelBase
         NotifySummaryProperties();
     }
 
+    partial void OnIncludeGuestsChanged(bool value)
+    {
+        DirectoryUsersView.Refresh();
+        OnPropertyChanged(nameof(DirectoryUserCount));
+    }
+
+    partial void OnDirectoryFilterTextChanged(string value)
+    {
+        DirectoryUsersView.Refresh();
+        OnPropertyChanged(nameof(DirectoryUserCount));
+    }
+
+    partial void OnIsLoadingDirectoryChanged(bool value)
+    {
+        LoadDirectoryCommand.NotifyCanExecuteChanged();
+        CancelDirectoryLoadCommand.NotifyCanExecuteChanged();
+    }
+
     // ── Internal helpers ─────────────────────────────────────────────────────
 
     /// <summary>Sets the current tenant profile (for test injection).</summary>
@@ -294,6 +387,91 @@ public partial class UserAccessAuditViewModel : FeatureViewModelBase
     internal Task TestRunOperationAsync(CancellationToken ct, IProgress<OperationProgress> progress)
         => RunOperationAsync(ct, progress);
 
+    // ── Directory browse mode ──────────────────────────────────────────────
+
+    private async Task LoadDirectoryAsync()
+    {
+        if (_graphUserDirectoryService is null) return;
+        var clientId = _currentProfile?.ClientId;
+        if (string.IsNullOrEmpty(clientId))
+        {
+            StatusMessage = "No tenant profile selected. Please connect first.";
+            return;
+        }
+
+        _directoryCts?.Cancel();
+        _directoryCts?.Dispose();
+        _directoryCts = new CancellationTokenSource();
+        var ct = _directoryCts.Token;
+
+        IsLoadingDirectory = true;
+        DirectoryLoadStatus = "Loading...";
+        try
+        {
+            var progress = new Progress<int>(count =>
+                DirectoryLoadStatus = $"Loading... {count} users");
+
+            var users = await _graphUserDirectoryService.GetUsersAsync(
+                clientId, includeGuests: true, progress, ct);
+
+            ct.ThrowIfCancellationRequested();
+
+            var dispatcher = Application.Current?.Dispatcher;
+            if (dispatcher != null)
+            {
+                await dispatcher.InvokeAsync(() => PopulateDirectory(users));
+            }
+            else
+            {
+                PopulateDirectory(users);
+            }
+
+            DirectoryLoadStatus = $"{users.Count} users loaded";
+        }
+        catch (OperationCanceledException)
+        {
+            DirectoryLoadStatus = "Load cancelled.";
+        }
+        catch (Exception ex)
+        {
+            DirectoryLoadStatus = $"Failed: {ex.Message}";
+            _logger.LogError(ex, "Directory load failed.");
+        }
+        finally
+        {
+            IsLoadingDirectory = false;
+        }
+    }
+
+    private void PopulateDirectory(IReadOnlyList<GraphDirectoryUser> users)
+    {
+        DirectoryUsers.Clear();
+        foreach (var u in users)
+            DirectoryUsers.Add(u);
+        DirectoryUsersView.Refresh();
+        OnPropertyChanged(nameof(DirectoryUserCount));
+    }
+
+    private bool DirectoryFilterPredicate(object obj)
+    {
+        if (obj is not GraphDirectoryUser user) return false;
+
+        // Member/guest filter
+        if (!IncludeGuests && !string.Equals(user.UserType, "Member", StringComparison.OrdinalIgnoreCase))
+            return false;
+
+        // Text filter
+        if (string.IsNullOrWhiteSpace(DirectoryFilterText)) return true;
+        var filter = DirectoryFilterText.Trim();
+        return user.DisplayName.Contains(filter, StringComparison.OrdinalIgnoreCase)
+            || user.UserPrincipalName.Contains(filter, StringComparison.OrdinalIgnoreCase)
+            || (user.Department?.Contains(filter, StringComparison.OrdinalIgnoreCase) ?? false)
+            || (user.JobTitle?.Contains(filter, StringComparison.OrdinalIgnoreCase) ?? false);
+    }
+
+    /// <summary>Exposes LoadDirectoryAsync for unit tests (internal + InternalsVisibleTo).</summary>
+    internal Task TestLoadDirectoryAsync() => LoadDirectoryAsync();
+
     // ── Command implementations ───────────────────────────────────────────────
 
     private bool CanExport() => Results.Count > 0;