public QueryHistoryProvider()
{
_historySourceList = new SourceList <RawQueryHistory>();
var counter = _historySourceList.CountChanged.Subscribe(i => IsEmpty = i == 0);
var limiter = _historySourceList.LimitSizeTo(100).Subscribe();
_historySourceList.AddRange(LoadFileData());
var sharedList = _historySourceList
.Connect()
.DeferUntilLoaded()
.Sort(SortExpressionComparer <RawQueryHistory> .Descending(t => t.LastRunAt))
.ObserveOnDispatcher()
.Bind(out _queryHistories)
.Subscribe();
var disposable = _queryHistories
.ObserveCollectionChanges()
.Throttle(TimeSpan.FromSeconds(2))
.Subscribe(pattern => { SaveFileData(_queryHistories); });
_compositeDisposable = new CompositeDisposable(counter, limiter, sharedList, disposable);
}
/// <summary>
/// Aggregates observables from <paramref name="collection"/> using selector for observables <paramref name="observablePropertySelector"/>
/// and aggregator for values from observables <paramref name="aggregator"/>
/// </summary>
public static IObservable <TRes> AggregateLatest <T, TRes>(
this ReadOnlyObservableCollection <T> collection,
Func <T, IObservable <TRes> > observablePropertySelector,
Func <IList <TRes>, TRes> aggregator)
{
return(Observable.Create <TRes>(observer =>
{
var aggregateLatestSubscription = collection.AggregateLatest(observablePropertySelector, aggregator, observer);
var collectionChangesSubscription = collection.ObserveCollectionChanges().Subscribe(_ =>
{
aggregateLatestSubscription.Dispose();
aggregateLatestSubscription = collection.AggregateLatest(observablePropertySelector, aggregator, observer);
});
return Disposable.Create(() =>
{
collectionChangesSubscription.Dispose();
aggregateLatestSubscription.Dispose();
});
}));
}
