Add the ability to specifiy additional paramenters when requesting items to IncrementalLoadingCollection
This commit is contained in:
Marco Minerva
Родитель
21d6d11d98
Коммит
0480710c88
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@ -6,10 +6,12 @@ public class Person
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public string Name { get; set; }
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}
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public class PeopleSource : IIncrementalSource<Person>
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public class PeopleSource : IIncrementalSource<Person, string>
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{
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private readonly List<Person> people;
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public string Arguments { get; set; }
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public PeopleSource()
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{
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// Creates an example collection.
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@ -24,9 +26,14 @@ public class PeopleSource : IIncrementalSource<Person>
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public async Task<IEnumerable<Person>> GetPagedItemsAsync(int pageIndex, int pageSize)
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{
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// Gets items from the collection according to pageIndex and pageSize parameters.
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var result = (from p in people
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select p).Skip(pageIndex * pageSize).Take(pageSize);
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// Gets items from the collection according to pageIndex and pageSize parameters, taking
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// care of the Arguments property.
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var result = (from p in _people
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select p).Skip(pageIndex * pageSize).Take(pageSize)
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.Select(p => new Person
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{
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Name = $"{p.Name} (requested at: {Arguments})"
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});
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// Simulates a longer request...
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await Task.Delay(1000);
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@ -37,7 +44,13 @@ public class PeopleSource : IIncrementalSource<Person>
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// IncrementalLoadingCollection can be bound to a GridView or a ListView. In this case it is a ListView called PeopleListView.
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var collection = new IncrementalLoadingCollection<PeopleSource, Person>();
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var collection = new IncrementalLoadingCollection<PeopleSource, Person, string>(() =>
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{
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// Simulates a method that sends additional paremeters to the source.
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var now = DateTime.Now;
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return Task.FromResult(now.ToString());
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});
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PeopleListView.ItemsSource = collection;
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// Binds the collection to the page DataContext in order to use its IsLoading and HasMoreItems properties.
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@ -11,6 +11,7 @@
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// ******************************************************************
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using System;
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using System.Threading.Tasks;
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using Windows.UI.Core;
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using Windows.UI.Xaml.Navigation;
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@ -40,7 +41,12 @@ namespace Microsoft.Toolkit.Uwp.SampleApp.SamplePages
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base.OnNavigatedTo(e);
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// IncrementalLoadingCollection can be bound to a GridView or a ListView. In this case it is a ListView called PeopleListView.
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var collection = new IncrementalLoadingCollection<PeopleSource, Person>();
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var collection = new IncrementalLoadingCollection<PeopleSource, Person, string>(() =>
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{
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// Simulates a method that sends additional paremeters to the source.
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var now = DateTime.Now;
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return Task.FromResult(now.ToString());
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});
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PeopleListView.ItemsSource = collection;
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@ -19,13 +19,18 @@ using System.Threading.Tasks;
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namespace Microsoft.Toolkit.Uwp.SampleApp.SamplePages
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{
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/// <summary>
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/// A sample implementation of the <see cref="IIncrementalSource{TSource}"/> interface.
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/// A sample implementation of the <see cref="IIncrementalSource{TSource,TArgs}"/> interface.
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/// </summary>
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/// <seealso cref="IIncrementalSource{TSource}"/>
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public class PeopleSource : IIncrementalSource<Person>
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/// <seealso cref="IIncrementalSource{TSource,TArgs}"/>
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public class PeopleSource : IIncrementalSource<Person, string>
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{
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private readonly List<Person> _people;
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/// <summary>
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/// Gets or sets a value indicating additional arguments used to perform data pagination (for example, they can be search paramenters).
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/// </summary>
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public string Arguments { get; set; }
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/// <summary>
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/// Initializes a new instance of the <see cref="PeopleSource"/> class.
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/// </summary>
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@ -55,11 +60,17 @@ namespace Microsoft.Toolkit.Uwp.SampleApp.SamplePages
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/// </param>
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/// <returns>
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/// Returns a collection of <see cref="Person"/>.
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/// </returns>
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public async Task<IEnumerable<Person>> GetPagedItemsAsync(int pageIndex, int pageSize, CancellationToken cancellationToken = default(CancellationToken))
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{
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// Gets items from the collection according to pageIndex and pageSize parameters.
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// Gets items from the collection according to pageIndex and pageSize parameters, taking
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// care of the Arguments property.
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var result = (from p in _people
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select p).Skip(pageIndex * pageSize).Take(pageSize);
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select p).Skip(pageIndex * pageSize).Take(pageSize)
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.Select(p => new Person
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{
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Name = $"{p.Name} (requested at: {Arguments})"
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});
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// Simulates a longer request...
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await Task.Delay(1000);
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@ -33,7 +33,7 @@ namespace Microsoft.Toolkit.Uwp.UI.Controls
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private Uri _uri;
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private bool _isHttpSource;
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/// <summary>
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/// Gets or sets get or set the source used by the image
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/// </summary>
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@ -0,0 +1,33 @@
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// ******************************************************************
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// Copyright (c) Microsoft. All rights reserved.
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// This code is licensed under the MIT License (MIT).
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// THE CODE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
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// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH
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// THE CODE OR THE USE OR OTHER DEALINGS IN THE CODE.
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// ******************************************************************
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using System;
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using System.Collections.Generic;
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using System.Threading;
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using System.Threading.Tasks;
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namespace Microsoft.Toolkit.Uwp
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{
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/// <summary>
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/// This interface represents a data source whose items can be loaded incrementally using the specified arguments as input (for example, they can be a search parameter).
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/// </summary>
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/// <typeparam name="TSource">Type of collection element.</typeparam>
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/// <typeparam name="TArgs">Type of input arguments.</typeparam>
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/// <seealso cref="IncrementalLoadingCollection{TSource, IType}"/>
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public interface IIncrementalSource<TSource, TArgs> : IIncrementalSource<TSource>
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{
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/// <summary>
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/// Gets or sets a value of <typeparamref name="TArgs"/> type that specifies additional loading parameters.
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/// </summary>
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TArgs Arguments { get; set; }
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}
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}
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@ -0,0 +1,90 @@
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// ******************************************************************
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// Copyright (c) Microsoft. All rights reserved.
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// This code is licensed under the MIT License (MIT).
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// THE CODE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
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// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH
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// THE CODE OR THE USE OR OTHER DEALINGS IN THE CODE.
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// ******************************************************************
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using System;
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using System.Collections.Generic;
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using System.Collections.ObjectModel;
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using System.ComponentModel;
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using System.Linq;
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using System.Runtime.InteropServices.WindowsRuntime;
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using System.Threading;
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using System.Threading.Tasks;
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using Windows.Foundation;
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using Windows.UI.Core;
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using Windows.UI.Xaml;
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using Windows.UI.Xaml.Data;
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namespace Microsoft.Toolkit.Uwp
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{
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/// <summary>
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/// This class represents an <see cref="ObservableCollection{IType}"/> whose items can be loaded incrementally using the specified arguments as input (for example, they can be a search parameter).
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/// </summary>
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/// <typeparam name="TSource">
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/// The data source that must be loaded incrementally.
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/// </typeparam>
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/// <typeparam name="IType">
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/// The type of collection items.
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/// </typeparam>
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/// <typeparam name="TArgs">
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/// Type of input arguments.
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/// </typeparam>
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/// <seealso cref="IIncrementalSource{TSource,TArgs}"/>
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/// <seealso cref="ISupportIncrementalLoading"/>
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public class IncrementalLoadingCollection<TSource, IType, TArgs> : IncrementalLoadingCollection<TSource, IType>
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where TSource : IIncrementalSource<IType, TArgs>, new()
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{
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private readonly Func<Task<TArgs>> _onGetArguments;
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/// <summary>
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/// Initializes a new instance of the <see cref="IncrementalLoadingCollection{TSource, IType, TArgs}"/> class, specifiyng a method that will be invoked to provide additional parameters for incremental loading (for example, a search query) and, optionally, how many items to load for each data page.
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/// </summary>
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/// <param name="onGetArguments">
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/// An asynchronous <see cref="Task"/> that will be invoked to provide additional parameters for incremental loading (for example, a search query).
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/// </param>
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/// <param name="itemsPerPage">
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/// The number of items to retrieve for each call. Default is 20.
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/// </param>
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/// <param name="onStartLoading">
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/// An <see cref="Action"/> that is called when a retrieval operation begins.
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/// </param>
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/// <param name="onEndLoading">
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/// An <see cref="Action"/> that is called when a retrieval operation ends.
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/// </param>
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/// <param name="onError">
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/// An <see cref="Action"/> that is called if an error occours during data retrieval.
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/// </param>
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public IncrementalLoadingCollection(Func<Task<TArgs>> onGetArguments, int itemsPerPage = 20, Action onStartLoading = null, Action onEndLoading = null, Action<Exception> onError = null)
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: base(itemsPerPage, onStartLoading, onEndLoading, onError)
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{
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_onGetArguments = onGetArguments;
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}
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/// <summary>
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/// Actually performs the incremental loading using the specified arguments as input.
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/// </summary>
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/// <param name="cancellationToken">
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/// Used to propagate notification that operation should be canceled.
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/// </param>
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/// <returns>
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/// Returns a collection of <typeparamref name="IType"/>.
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/// </returns>
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protected override async Task<IEnumerable<IType>> LoadDataAsync(CancellationToken cancellationToken)
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{
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// Before call the actual pagination method, sets the source arguments.
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var args = await _onGetArguments.Invoke();
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Source.Arguments = args;
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var result = await Source.GetPagedItemsAsync(CurrentPageIndex++, ItemsPerPage, cancellationToken);
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return result;
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}
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}
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}
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@ -40,18 +40,28 @@ namespace Microsoft.Toolkit.Uwp
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ISupportIncrementalLoading
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where TSource : IIncrementalSource<IType>, new()
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{
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private readonly TSource _source;
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/// <summary>
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/// Gets a value indicating the source of incremental loading.
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/// </summary>
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protected TSource Source { get; }
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/// <summary>
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/// Gets a value indicating how many items that must be retrieved for each incremental call.
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/// </summary>
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protected int ItemsPerPage { get; }
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/// <summary>
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/// Gets or sets a value indicating The zero-based index of the current items page.
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/// </summary>
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protected int CurrentPageIndex { get; set; }
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private readonly Action _onStartLoading;
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private readonly Action _onEndLoading;
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private readonly Action<Exception> _onError;
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private readonly int _itemsPerPage;
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private int _currentPageIndex;
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private CancellationToken _cancellationToken;
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private bool _isLoading;
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private bool _hasMoreItems;
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private CancellationToken _cancellationToken;
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/// <summary>
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/// Gets a value indicating whether new items are being loaded.
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@ -124,13 +134,13 @@ namespace Microsoft.Toolkit.Uwp
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/// </param>
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public IncrementalLoadingCollection(int itemsPerPage = 20, Action onStartLoading = null, Action onEndLoading = null, Action<Exception> onError = null)
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{
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_source = new TSource();
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Source = new TSource();
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_onStartLoading = onStartLoading;
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_onEndLoading = onEndLoading;
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_onError = onError;
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_itemsPerPage = itemsPerPage;
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ItemsPerPage = itemsPerPage;
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_hasMoreItems = true;
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}
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@ -146,6 +156,21 @@ namespace Microsoft.Toolkit.Uwp
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public IAsyncOperation<LoadMoreItemsResult> LoadMoreItemsAsync(uint count)
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=> AsyncInfo.Run((c) => LoadMoreItemsAsync(count, c));
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/// <summary>
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/// Actually performs the incremental loading.
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/// </summary>
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/// <param name="cancellationToken">
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/// Used to propagate notification that operation should be canceled.
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/// </param>
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/// <returns>
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/// Returns a collection of <typeparamref name="IType"/>.
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/// </returns>
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protected virtual async Task<IEnumerable<IType>> LoadDataAsync(CancellationToken cancellationToken)
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{
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var result = await Source.GetPagedItemsAsync(CurrentPageIndex++, ItemsPerPage, cancellationToken);
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return result;
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}
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private async Task<LoadMoreItemsResult> LoadMoreItemsAsync(uint count, CancellationToken cancellationToken)
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{
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uint resultCount = 0;
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@ -159,7 +184,7 @@ namespace Microsoft.Toolkit.Uwp
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try
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{
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IsLoading = true;
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data = await LoadDataAsync(count, _cancellationToken);
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data = await LoadDataAsync(_cancellationToken);
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}
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catch (OperationCanceledException)
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{
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@ -198,11 +223,5 @@ namespace Microsoft.Toolkit.Uwp
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return new LoadMoreItemsResult { Count = resultCount };
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}
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private async Task<IEnumerable<IType>> LoadDataAsync(uint count, CancellationToken cancellationToken)
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{
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var result = await _source.GetPagedItemsAsync(_currentPageIndex++, _itemsPerPage, cancellationToken);
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return result;
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}
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}
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}
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@ -63,8 +63,10 @@
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<Compile Include="Helpers\HttpHelperResponse.cs" />
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<Compile Include="Helpers\StorageFileHelper.cs" />
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<Compile Include="Helpers\WeakEventListener.cs" />
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<Compile Include="IncrementalLoadingCollection\IIncrementalSource.cs" />
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<Compile Include="IncrementalLoadingCollection\IncrementalLoadingCollection.cs" />
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<Compile Include="IncrementalLoadingCollection\IIncrementalSource{TSource,TArgs}.cs" />
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<Compile Include="IncrementalLoadingCollection\IIncrementalSource{TSource}.cs" />
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<Compile Include="IncrementalLoadingCollection\IncrementalLoadingCollection{TSource,IType,TArgs}.cs" />
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<Compile Include="IncrementalLoadingCollection\IncrementalLoadingCollection{TSource,IType}.cs" />
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<Compile Include="Properties\AssemblyInfo.cs" />
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<Compile Include="Helpers\StreamHelper.cs" />
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<Compile Include="Structures\HslColor.cs" />
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