Skip to content

Commit e348f61

Browse files
author
msftbot[bot]
authored
incremnenralLoading-pageIndex-fix (#3852)
<!-- 🚨 Please Do Not skip any instructions and information mentioned below as they are all required and essential to evaluate and test the PR. By fulfilling all the required information you will be able to reduce the volume of questions and most likely help merge the PR faster 🚨 --> <!-- 📝 It is preferred if you keep the "☑️ Allow edits by maintainers" checked in the Pull Request Template as it increases collaboration with the Toolkit maintainers by permitting commits to your PR branch (only) created from your fork. This can let us quickly make fixes for minor typos or forgotten StyleCop issues during review without needing to wait on you doing extra work. Let us help you help us! 🎉 --> ## Fixes #3841 <!-- Add the relevant issue number after the "#" mentioned above (for ex: Fixes #1234) which will automatically close the issue once the PR is merged. --> <!-- Add a brief overview here of the feature/bug & fix. --> Only Increment CurrentPageIndex if Source.GetPagedItemsAsync's task completes with RanToCompletion ## PR Type What kind of change does this PR introduce? <!-- Please uncomment one or more that apply to this PR. --> - Bugfix <!-- - Feature --> <!-- - Code style update (formatting) --> <!-- - Refactoring (no functional changes, no api changes) --> <!-- - Build or CI related changes --> <!-- - Documentation content changes --> <!-- - Sample app changes --> <!-- - Other... Please describe: --> ## What is the current behavior? <!-- Please describe the current behavior that you are modifying, or link to a relevant issue. --> `CurrentPageIndex` is incremented before `GetPagedItemsAsync` completes. If it does not complete or fails it is still incremented. ## What is the new behavior? <!-- Describe how was this issue resolved or changed? --> `CurrentPageIndex` is only incremented once `GetPagedItemsAsync`'s Task completes with `RanToCompletion. ## PR Checklist Please check if your PR fulfills the following requirements: - [ ] Tested code with current [supported SDKs](../readme.md#supported) - [ ] Pull Request has been submitted to the documentation repository [instructions](..\contributing.md#docs). Link: <!-- docs PR link --> - [ ] Sample in sample app has been added / updated (for bug fixes / features) - [ ] Icon has been created (if new sample) following the [Thumbnail Style Guide and templates](https://github.com/windows-toolkit/WindowsCommunityToolkit-design-assets) - [ ] New major technical changes in the toolkit have or will be added to the [Wiki](https://github.com/windows-toolkit/WindowsCommunityToolkit/wiki) e.g. build changes, source generators, testing infrastructure, sample creation changes, etc... - [ ] Tests for the changes have been added (for bug fixes / features) (if applicable) - [ ] Header has been added to all new source files (run *build/UpdateHeaders.bat*) - [ ] Contains **NO** breaking changes <!-- If this PR contains a breaking change, please describe the impact and migration path for existing applications below. Please note that breaking changes are likely to be rejected within minor release cycles or held until major versions. --> ## Other information
2 parents 529624c + 70e9271 commit e348f61

File tree

4 files changed

+231
-2
lines changed

4 files changed

+231
-2
lines changed

‎Microsoft.Toolkit.Uwp/IncrementalLoadingCollection/IncrementalLoadingCollection.cs

Lines changed: 24 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -30,6 +30,8 @@ public class IncrementalLoadingCollection<TSource, IType> : ObservableCollection
3030
ISupportIncrementalLoading
3131
where TSource : Collections.IIncrementalSource<IType>
3232
{
33+
private readonly SemaphoreSlim _mutex = new SemaphoreSlim(1);
34+
3335
/// <summary>
3436
/// Gets or sets an <see cref="Action"/> that is called when a retrieval operation begins.
3537
/// </summary>
@@ -226,7 +228,23 @@ public Task RefreshAsync()
226228
/// </returns>
227229
protected virtual async Task<IEnumerable<IType>> LoadDataAsync(CancellationToken cancellationToken)
228230
{
229-
var result = await Source.GetPagedItemsAsync(CurrentPageIndex++, ItemsPerPage, cancellationToken);
231+
var result = await Source.GetPagedItemsAsync(CurrentPageIndex, ItemsPerPage, cancellationToken)
232+
.ContinueWith(
233+
t =>
234+
{
235+
if(t.IsFaulted)
236+
{
237+
throw t.Exception;
238+
}
239+
240+
if (t.IsCompletedSuccessfully)
241+
{
242+
CurrentPageIndex += 1;
243+
}
244+
245+
return t.Result;
246+
}, cancellationToken);
247+
230248
return result;
231249
}
232250

@@ -235,6 +253,9 @@ private async Task<LoadMoreItemsResult> LoadMoreItemsAsync(uint count, Cancellat
235253
uint resultCount = 0;
236254
_cancellationToken = cancellationToken;
237255

256+
// TODO (2021.05.05): Make use common AsyncMutex class.
257+
// AsyncMutex is located at Microsoft.Toolkit.Uwp.UI.Media/Extensions/System.Threading.Tasks/AsyncMutex.cs at the time of this note.
258+
await _mutex.WaitAsync();
238259
try
239260
{
240261
if (!_cancellationToken.IsCancellationRequested)
@@ -278,6 +299,8 @@ private async Task<LoadMoreItemsResult> LoadMoreItemsAsync(uint count, Cancellat
278299
_refreshOnLoad = false;
279300
await RefreshAsync();
280301
}
302+
303+
_mutex.Release();
281304
}
282305

283306
return new LoadMoreItemsResult { Count = resultCount };

‎UnitTests/UnitTests.UWP/UI/Collection/DataSource.cs

Lines changed: 59 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,59 @@
1+
// Licensed to the .NET Foundation under one or more agreements.
2+
// The .NET Foundation licenses this file to you under the MIT license.
3+
// See the LICENSE file in the project root for more information.
4+
5+
using Microsoft.Toolkit.Collections;
6+
using System;
7+
using System.Collections.Generic;
8+
using System.Linq;
9+
using System.Threading;
10+
using System.Threading.Tasks;
11+
12+
namespace UnitTests.UI
13+
{
14+
public class DataSource<T> : IIncrementalSource<T>
15+
{
16+
private readonly IEnumerable<T> items;
17+
private readonly Queue<PageOperation> pageRequestOperations;
18+
19+
public delegate IEnumerable<T> PageOperation(IEnumerable<T> page);
20+
21+
public DataSource(IEnumerable<T> items, IEnumerable<PageOperation> pageOps)
22+
: this(items, new Queue<PageOperation>(pageOps))
23+
{
24+
}
25+
26+
public DataSource(IEnumerable<T> items, params PageOperation[] pageOps)
27+
: this(items, new Queue<PageOperation>(pageOps))
28+
{
29+
}
30+
31+
public DataSource(IEnumerable<T> items, Queue<PageOperation> pageOps = default)
32+
{
33+
this.items = items ?? throw new ArgumentNullException(nameof(items));
34+
this.pageRequestOperations = pageOps ?? new Queue<PageOperation>();
35+
}
36+
37+
public static PageOperation MakeDelayOp(int delay)
38+
=> new (page =>
39+
{
40+
Thread.Sleep(delay);
41+
return page;
42+
});
43+
44+
public static IEnumerable<T> ThrowException(IEnumerable<T> page) => throw new Exception();
45+
46+
public static IEnumerable<T> PassThrough(IEnumerable<T> page) => page;
47+
48+
public async Task<IEnumerable<T>> GetPagedItemsAsync(int pageIndex, int pageSize, CancellationToken cancellationToken = default)
49+
{
50+
// Gets items from the collection according to pageIndex and pageSize parameters.
51+
var result = (from p in items
52+
select p).Skip(pageIndex * pageSize).Take(pageSize);
53+
54+
return this.pageRequestOperations.TryDequeue(out var op)
55+
? await Task.Factory.StartNew(new Func<object, IEnumerable<T>>(o => op(o as IEnumerable<T>)), state: result)
56+
: result;
57+
}
58+
}
59+
}

‎UnitTests/UnitTests.UWP/UI/Collection/Test_IncrementalLoadingCollection.cs

Lines changed: 145 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,145 @@
1+
// Licensed to the .NET Foundation under one or more agreements.
2+
// The .NET Foundation licenses this file to you under the MIT license.
3+
// See the LICENSE file in the project root for more information.
4+
5+
using System;
6+
using System.Collections.Generic;
7+
using System.Linq;
8+
using System.Threading;
9+
using System.Threading.Tasks;
10+
using Microsoft.Toolkit.Uwp;
11+
using Microsoft.VisualStudio.TestTools.UnitTesting;
12+
13+
namespace UnitTests.UI
14+
{
15+
[TestClass]
16+
public class Test_IncrementalLoadingCollection
17+
{
18+
private const int PageSize = 20;
19+
private const int Pages = 5;
20+
21+
private static readonly DataSource<int>.PageOperation[] FailPassSequence
22+
= new DataSource<int>.PageOperation[]
23+
{
24+
DataSource<int>.ThrowException, DataSource<int>.PassThrough,
25+
DataSource<int>.ThrowException, DataSource<int>.PassThrough,
26+
DataSource<int>.ThrowException, DataSource<int>.PassThrough,
27+
DataSource<int>.ThrowException, DataSource<int>.PassThrough,
28+
DataSource<int>.ThrowException, DataSource<int>.PassThrough,
29+
};
30+
31+
private static readonly int[] AllData
32+
= Enumerable.Range(0, Pages * PageSize).ToArray();
33+
34+
[DataRow]
35+
[DataRow(2500, 1000, 1000, 1000, 1000)]
36+
[TestMethod]
37+
public async Task Requests(params int[] pageDelays)
38+
{
39+
var source = new DataSource<int>(AllData, pageDelays.Select(DataSource<int>.MakeDelayOp));
40+
var collection = new IncrementalLoadingCollection<DataSource<int>, int>(source, PageSize);
41+
42+
for (int pageNum = 1; pageNum <= Pages; pageNum++)
43+
{
44+
await collection.LoadMoreItemsAsync(0);
45+
CollectionAssert.AreEqual(Enumerable.Range(0, PageSize * pageNum).ToArray(), collection);
46+
}
47+
}
48+
49+
[DataRow]
50+
[DataRow(2500, 1000, 1000, 1000, 1000)]
51+
[TestMethod]
52+
public async Task RequestsAsync(params int[] pageDelays)
53+
{
54+
var source = new DataSource<int>(AllData, pageDelays.Select(DataSource<int>.MakeDelayOp));
55+
var collection = new IncrementalLoadingCollection<DataSource<int>, int>(source, PageSize);
56+
57+
var requests = new List<Task>();
58+
59+
for (int pageNum = 1; pageNum <= Pages; pageNum++)
60+
{
61+
requests.Add(collection.LoadMoreItemsAsync(0).AsTask()
62+
.ContinueWith(t => Assert.IsTrue(t.IsCompletedSuccessfully)));
63+
}
64+
65+
await Task.WhenAll(requests);
66+
67+
CollectionAssert.AreEqual(AllData, collection);
68+
}
69+
70+
[TestMethod]
71+
public async Task FirstRequestFails()
72+
{
73+
var source = new DataSource<int>(AllData, DataSource<int>.ThrowException);
74+
var collection = new IncrementalLoadingCollection<DataSource<int>, int>(source, PageSize);
75+
76+
await Assert.ThrowsExceptionAsync<AggregateException>(collection.LoadMoreItemsAsync(0).AsTask);
77+
78+
Assert.IsTrue(!collection.Any());
79+
80+
var requests = new List<Task>();
81+
82+
for (int pageNum = 1; pageNum <= Pages; pageNum++)
83+
{
84+
requests.Add(collection.LoadMoreItemsAsync(0).AsTask()
85+
.ContinueWith(t => Assert.IsTrue(t.IsCompletedSuccessfully)));
86+
}
87+
88+
await Task.WhenAll(requests);
89+
90+
CollectionAssert.AreEqual(AllData, collection);
91+
}
92+
93+
[TestMethod]
94+
public async Task EveryOtherRequestFails()
95+
{
96+
var source = new DataSource<int>(AllData, FailPassSequence);
97+
var collection = new IncrementalLoadingCollection<DataSource<int>, int>(source, PageSize);
98+
99+
var willFail = true;
100+
for (int submitedRequests = 0; submitedRequests < Pages * 2; submitedRequests++)
101+
{
102+
if (willFail)
103+
{
104+
await Assert.ThrowsExceptionAsync<AggregateException>(collection.LoadMoreItemsAsync(0).AsTask);
105+
}
106+
else
107+
{
108+
await collection.LoadMoreItemsAsync(0);
109+
}
110+
111+
willFail = !willFail;
112+
}
113+
114+
CollectionAssert.AreEqual(AllData, collection);
115+
}
116+
117+
[TestMethod]
118+
public async Task EveryOtherRequestFailsAsync()
119+
{
120+
var source = new DataSource<int>(AllData, FailPassSequence);
121+
var collection = new IncrementalLoadingCollection<DataSource<int>, int>(source, PageSize);
122+
123+
var requests = new List<Task>();
124+
125+
var willFail = true;
126+
for (int submitedRequests = 0; submitedRequests < Pages * 2; submitedRequests++)
127+
{
128+
if (willFail)
129+
{
130+
requests.Add(Assert.ThrowsExceptionAsync<AggregateException>(collection.LoadMoreItemsAsync(0).AsTask));
131+
}
132+
else
133+
{
134+
requests.Add(collection.LoadMoreItemsAsync(0).AsTask().ContinueWith(t => Assert.IsTrue(t.IsCompletedSuccessfully)));
135+
}
136+
137+
willFail = !willFail;
138+
}
139+
140+
await Task.WhenAll(requests);
141+
142+
CollectionAssert.AreEqual(AllData, collection);
143+
}
144+
}
145+
}

‎UnitTests/UnitTests.UWP/UnitTests.UWP.csproj

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -197,6 +197,8 @@
197197
<Compile Include="Properties\AssemblyInfo.cs" />
198198
<Compile Include="Helpers\Test_WeakEventListener.cs" />
199199
<Compile Include="UI\Animations\Test_AnimationBuilderStart.cs" />
200+
<Compile Include="UI\Collection\DataSource.cs" />
201+
<Compile Include="UI\Collection\Test_IncrementalLoadingCollection.cs" />
200202
<Compile Include="UI\Controls\Test_Carousel.cs" />
201203
<Compile Include="UI\Controls\Test_BladeView.cs" />
202204
<Compile Include="UI\Controls\Test_RadialGauge.cs" />
@@ -548,4 +550,4 @@
548550
<Target Name="AfterBuild">
549551
</Target>
550552
-->
551-
</Project>
553+
</Project>

0 commit comments

Comments
 (0)