public override async Task <object> Load(CancellationToken ct, IDataLoaderRequest request)
{
var value = request.Context[SubscribeToDataTrigger.DataContextKey];
if (value != null)
{
return(value);
}
else if (request.Context[SubscribeToDataTrigger.ErrorContextKey] is Exception error)
{
throw error;
}
else
{
if (_subscription != null)
{
_subscription.Dispose();
}
var data = await base.Load(ct, request);
_subscription = _subscribeToData(data);
return(data);
}
}
/// <summary>
/// Creates a new instance of <see cref="DataLoaderState"/>.
/// </summary>
/// <param name="request">The <see cref="IDataLoaderRequest"/>.</param>
/// <returns>The <see cref="DataLoaderState"/>.</returns>
public DataLoaderState WithRequest(IDataLoaderRequest request)
{
return(new DataLoaderState(this)
{
Request = request
});
}
/// <inheritdoc />
public override Task <object> Load(CancellationToken ct, IDataLoaderRequest request)
{
return(Task.Run(InnerLoad));
Task <object> InnerLoad()
{
return(base.Load(ct, request));
}
}
public override async Task <object> Load(CancellationToken ct, IDataLoaderRequest request)
{
var result = await base.Load(ct, request);
if (_data != null)
{
_onPreviousDataLost(_data);
}
_data = result;
return(result);
}
public override async Task <object> Load(CancellationToken ct, IDataLoaderRequest request)
{
var result = await base.Load(ct, request);
// We should not dispose the previous data if we load the same instance.
if (_data != null && !ReferenceEquals(_data, result))
{
_onPreviousDataLost(_data);
}
_data = result;
return(result);
}
public override async Task <object> Load(CancellationToken ct, IDataLoaderRequest request)
{
try
{
var result = await base.Load(ct, request);
await _onSuccess(ct, request, result);
return(result);
}
catch (Exception error)
{
await _onError(ct, request, error);
throw;
}
}
/// <inheritdoc/>
public Task <object> Load(CancellationToken ct, IDataLoaderRequest request)
{
return(_dataLoaderDelegate(ct, request));
}
private async Task <ReadOnlyObservableCollection <ChuckNorrisItemViewModel> > LoadQuotes(CancellationToken ct, IDataLoaderRequest request)
{
var quotes = await this.GetService <IChuckNorrisService>().GetFavorites(ct);
// This is an observable list that will dynamically remove items when we unfavorite. We could use 'quotes.Items' if we don't want the list to remove items directly.
quotes
.Connect()
.Transform(q => this.GetChild(() => new ChuckNorrisItemViewModel(this, q), q.Id))
.ObserveOn(this.GetService <IDispatcherScheduler>())
.Bind(out var list)
.DisposeMany()
.Subscribe()
.DisposeWithNextLoad(request);
return(list);
}
/// <inheritdoc cref="IDataLoaderStrategy.Load(CancellationToken, IDataLoaderRequest)"/>
public virtual Task <object> Load(CancellationToken ct, IDataLoaderRequest request)
{
return(InnerStrategy.Load(ct, request));
}
/// <summary>
/// Adds this <paramref name="disposable"/> to the <see cref="IDataLoaderRequest"/>'s <see cref="SequenceDisposableGroup"/>.
/// </summary>
/// <param name="disposable">The disposable to add.</param>
/// <param name="request">The request that generated the <paramref name="disposable"/>.</param>
/// <returns>The original <paramref name="disposable"/>.</returns>
public static IDisposable DisposeWithNextLoad(this IDisposable disposable, IDataLoaderRequest request)
{
request.AddToSequenceDisposableGroup(disposable);
return(disposable);
}
/// <summary>
/// Adds a <paramref name="disposable"/> to this <paramref name="request"/>'s <see cref="SequenceDisposableGroup"/>.
/// </summary>
/// <param name="request">The request that generated the <paramref name="disposable"/>.</param>
/// <param name="disposable">The disposable to add.</param>
public static void AddToSequenceDisposableGroup(this IDataLoaderRequest request, IDisposable disposable)
{
var contextLifetime = request.Context.GetSequenceDisposableGroup();
contextLifetime.AddOrClear(request.SequenceId, disposable);
}
public override async Task <object> Load(CancellationToken ct, IDataLoaderRequest request)
{
return(await _innerFunc());
}
