added features to AsyncLoadingCollection for a possible integration with Windows Community Toolkit

Updated Readme
Updated vulnerable nuget package

Author: Licantrop0

MsGraphSamples.WinUI/Helpers/AsyncLoadingCollection.cs

@@ -2,37 +2,76 @@
 // Licensed under the MIT License.
 
 using System.Collections.ObjectModel;
+using System.ComponentModel;
 using Microsoft.UI.Xaml.Data;
 using Windows.Foundation;
 
 namespace MsGraphSamples.WinUI.Helpers;
 
-public class AsyncLoadingCollection<T>(IAsyncEnumerable<T> source, uint itemsPerPage = 25) : ObservableCollection<T>, ISupportIncrementalLoading
+/// <summary>
+/// Initializes a new instance of the <see cref="AsyncLoadingCollection{T}"/> class.
+/// </summary>
+/// <param name="source">The source of items to load asynchronously.</param>
+/// <param name="maxItemsPerPage">The maximum number of items to load per page.</param>
+/// <param name="OnStartLoading">The action to invoke when loading starts.</param>
+/// <param name="OnEndLoading">The action to invoke when loading ends.</param>
+/// <param name="OnError">The action to invoke when an error occurs during loading.</param>
+/// <param name="cancellationToken">The cancellation token to cancel the loading operation.</param>
+public class AsyncLoadingCollection<T>(
+    IAsyncEnumerable<T> source,
+    uint defaultItemsPerPage = 25,
+    CancellationToken cancellationToken = default)
+    : ObservableCollection<T>, ISupportIncrementalLoading
 {
-    private IAsyncEnumerator<T>? _asyncEnumerator = source.GetAsyncEnumerator();
+    private IAsyncEnumerator<T>? _asyncEnumerator = source
+        .GetAsyncEnumerator()
+        .WithCancellation(cancellationToken);
+
     private readonly SemaphoreSlim _mutex = new(1, 1);
+    public Action? OnStartLoading { get; set; }
+    public Action? OnEndLoading { get; set; }
+    public Action<Exception>? OnError { get; set; }
 
     public bool HasMoreItems => _asyncEnumerator != null;
 
-    public IAsyncOperation<LoadMoreItemsResult> LoadMoreItemsAsync(uint count = 0) =>
-        LoadMoreItemsAsync(count == 0 ? itemsPerPage : count, default)
+    private bool _isLoading;
+    /// <summary>
+    /// Gets a value indicating whether new items are being loaded.
+    /// </summary>
+    public bool IsLoading
+    {
+        get => _isLoading;
+
+        private set
+        {
+            if (value == _isLoading)
+                return;
+
+            _isLoading = value;
+            OnPropertyChanged(new PropertyChangedEventArgs(nameof(IsLoading)));
+
+            if (_isLoading)
+                OnStartLoading?.Invoke();
+            else
+                OnEndLoading?.Invoke();
+        }
+    }
+    public IAsyncOperation<LoadMoreItemsResult> LoadMoreItemsAsync(uint count) =>
+        LoadMoreItemsAsyncInternal(count)
         .AsAsyncOperation();
 
-    private async Task<LoadMoreItemsResult> LoadMoreItemsAsync(uint count, CancellationToken cancellationToken)
+    private async Task<LoadMoreItemsResult> LoadMoreItemsAsyncInternal(uint count)
     {
         await _mutex.WaitAsync(cancellationToken);
 
-        if (cancellationToken.IsCancellationRequested || !HasMoreItems)
-            return new LoadMoreItemsResult(0);
-
         uint itemsLoaded = 0;
-        var itemsToLoad = Math.Min(itemsPerPage, count);
+        IsLoading = true;
 
         try
         {
-            while (itemsLoaded < itemsToLoad)
+            while (itemsLoaded < count && HasMoreItems)
             {
-                if (await _asyncEnumerator!.MoveNextAsync(cancellationToken).ConfigureAwait(false))
+                if (await _asyncEnumerator!.MoveNextAsync().ConfigureAwait(false))
                 {
                     Add(_asyncEnumerator!.Current);
                     itemsLoaded++;
@@ -42,7 +81,6 @@ private async Task<LoadMoreItemsResult> LoadMoreItemsAsync(uint count, Cancellat
                     // Dispose the enumerator when we're done
                     await _asyncEnumerator!.DisposeAsync();
                     _asyncEnumerator = null;
-                    break;
                 }
             }
         }
@@ -52,17 +90,39 @@ private async Task<LoadMoreItemsResult> LoadMoreItemsAsync(uint count, Cancellat
             await _asyncEnumerator!.DisposeAsync();
             _asyncEnumerator = null;
         }
-        catch (Exception)
+        catch (Exception ex)
         {
+            OnError?.Invoke(ex);
             await _asyncEnumerator!.DisposeAsync();
             _asyncEnumerator = null;
             throw;
         }
         finally
         {
+            IsLoading = false;
             _mutex.Release();
         }
 
         return new LoadMoreItemsResult(itemsLoaded);
     }
+
+    /// <summary>
+    /// Clears the collection and triggers/forces a reload of the first page
+    /// </summary>
+    /// <returns>
+    /// An object of the <see cref="LoadMoreItemsAsync(uint)"/> that specifies how many items have been actually retrieved.
+    /// </returns>
+    public async Task<LoadMoreItemsResult> RefreshAsync()
+    {
+        await _mutex.WaitAsync(cancellationToken);
+
+        Clear();
+        _asyncEnumerator = source
+            .GetAsyncEnumerator()
+            .WithCancellation(cancellationToken);
+
+        _mutex.Release();
+
+        return await LoadMoreItemsAsync(defaultItemsPerPage);
+    }
 }

MsGraphSamples.WinUI/ViewModels/MainViewModel.cs

@@ -20,7 +20,7 @@ public partial class MainViewModel(
     IAsyncEnumerableGraphDataService graphDataService,
     IDialogService dialogService) : ObservableRecipient
 {
-    private readonly ushort pageSize = 25;
+    public ushort PageSize { get; set; } = 25;
     private readonly Stopwatch _stopWatch = new();
     public long ElapsedMs => _stopWatch.ElapsedMilliseconds;
 
@@ -125,11 +125,11 @@ private Task Load()
         return IsBusyWrapper(SelectedEntity switch
         {
             //"Users" =>  _graphDataService.GetUsersInBatch(SplittedSelect, pageSize),
-            "Users" => graphDataService.GetUsers(SplittedSelect, Filter, SplittedOrderBy, Search, pageSize),
-            "Groups" => graphDataService.GetGroups(SplittedSelect, Filter, SplittedOrderBy, Search, pageSize),
-            "Applications" => graphDataService.GetApplications(SplittedSelect, Filter, SplittedOrderBy, Search, pageSize),
-            "ServicePrincipals" => graphDataService.GetServicePrincipals(SplittedSelect, Filter, SplittedOrderBy, Search, pageSize),
-            "Devices" => graphDataService.GetDevices(SplittedSelect, Filter, SplittedOrderBy, Search, pageSize),
+            "Users" => graphDataService.GetUsers(SplittedSelect, Filter, SplittedOrderBy, Search, PageSize),
+            "Groups" => graphDataService.GetGroups(SplittedSelect, Filter, SplittedOrderBy, Search, PageSize),
+            "Applications" => graphDataService.GetApplications(SplittedSelect, Filter, SplittedOrderBy, Search, PageSize),
+            "ServicePrincipals" => graphDataService.GetServicePrincipals(SplittedSelect, Filter, SplittedOrderBy, Search, PageSize),
+            "Devices" => graphDataService.GetDevices(SplittedSelect, Filter, SplittedOrderBy, Search, PageSize),
             _ => throw new NotImplementedException("Can't find selected entity")
         });
     }
@@ -144,11 +144,11 @@ public Task DrillDown()
 
         return IsBusyWrapper(SelectedEntity switch
         {
-            "Users" => graphDataService.GetTransitiveMemberOfAsGroups(SelectedObject.Id!, SplittedSelect, pageSize),
-            "Groups" => graphDataService.GetTransitiveMembersAsUsers(SelectedObject.Id!, SplittedSelect, pageSize),
-            "Applications" => graphDataService.GetApplicationOwnersAsUsers(SelectedObject.Id!, SplittedSelect, pageSize),
-            "ServicePrincipals" => graphDataService.GetServicePrincipalOwnersAsUsers(SelectedObject.Id!, SplittedSelect, pageSize),
-            "Devices" => graphDataService.GetDeviceOwnersAsUsers(SelectedObject.Id!, SplittedSelect, pageSize),
+            "Users" => graphDataService.GetTransitiveMemberOfAsGroups(SelectedObject.Id!, SplittedSelect, PageSize),
+            "Groups" => graphDataService.GetTransitiveMembersAsUsers(SelectedObject.Id!, SplittedSelect, PageSize),
+            "Applications" => graphDataService.GetApplicationOwnersAsUsers(SelectedObject.Id!, SplittedSelect, PageSize),
+            "ServicePrincipals" => graphDataService.GetServicePrincipalOwnersAsUsers(SelectedObject.Id!, SplittedSelect, PageSize),
+            "Devices" => graphDataService.GetDeviceOwnersAsUsers(SelectedObject.Id!, SplittedSelect, PageSize),
             _ => throw new NotImplementedException("Can't find selected entity")
         });
     }
@@ -199,10 +199,10 @@ private async Task IsBusyWrapper(IAsyncEnumerable<DirectoryObject> directoryObje
             // Sending message to generate DataGridColumns according to the selected properties
             await GetPropertiesAndSortDirection(directoryObjects);
 
-            DirectoryObjects = new(directoryObjects, pageSize);
+            DirectoryObjects = new(directoryObjects, PageSize);
 
             // Trigger load due to bug https://github.com/CommunityToolkit/WindowsCommunityToolkit/issues/3584
-            await DirectoryObjects.LoadMoreItemsAsync();
+            await DirectoryObjects.RefreshAsync();
 
             SelectedEntity = DirectoryObjects.FirstOrDefault() switch
             {

README.md

@@ -53,7 +53,7 @@ The main code is in [AsyncEnumerableGraphDataService.cs](MsGraphSamples.Services
 
 ## Prerequisites
 
-- Either [Visual Studio (>v16.8)](https://aka.ms/vsdownload) *or* [Visual Studio Code](https://code.visualstudio.com/) with [.NET 7.0 SDK](https://dotnet.microsoft.com/download/dotnet/7.0) and [C# for Visual Studio Code Extension](https://marketplace.visualstudio.com/items?itemName=ms-dotnettools.csharp)
+- Either [Visual Studio (>v16.8)](https://aka.ms/vsdownload) *or* [Visual Studio Code](https://code.visualstudio.com/) with [.NET 8.0 SDK](https://dotnet.microsoft.com/download/dotnet/8.0) and [C# for Visual Studio Code Extension](https://marketplace.visualstudio.com/items?itemName=ms-dotnettools.csharp)
 - A Microsoft Entra ID tenant. For more information, see [How to get an Microsoft Entra ID tenant](https://azure.microsoft.com/documentation/articles/active-directory-howto-tenant/)
 - A user account in your Microsoft Entra ID tenant. This sample will not work with a personal Microsoft account (formerly Windows Live account). Therefore, if you signed in to the [Azure portal](https://portal.azure.com) with a Microsoft account and have never created a user account in your directory before, you need to do that now.
 
@@ -91,7 +91,7 @@ or download and extract the repository .zip file.
 This application use the [.NET Core Secret Manager](https://docs.microsoft.com/aspnet/core/security/app-secrets) to store the **ClientId**.  
 To add the **ClientId** created on step 1 of registration:
 
-1. Open a **Developer Command Prompt** or an **Integrated Terminal** and locate the `dotnet-aad-query-sample\MSGraphSamples.WPF\` directory.
+1. Open a **Developer Command Prompt** or an **Integrated Terminal** and locate the `dotnet-aad-query-sample\MsGraphSamples.Services\` directory.
 1. Type `dotnet user-secrets set "clientId" "<YOUR CLIENT ID>"`
 
 ## Run the sample