Batch UI notifications

[lwsouzaaht]

Hello!

I have a very large cache, with 20K items, linked to a grid.
Currently, the grid updates every time the collection changes, but for performance reasons, I would like to batch, let's say, 200 changes before update the UI.

I tried to use Batch and other operator, but could no find good examples.

Here is the last part of my code:

        columnFilteredObservable
            .Filter(_filterSubject) // the "Counter" filter
            .Sort(this.WhenAnyObservable(model => model.CurrentSortFilter.SortObservable), SortOptimisations.None, 500)
            .ObserveOn(RxApp.MainThreadScheduler)
            .Bind(IncidentListItems)
            .Subscribe()
            .DisposeWith(_disposable);

[JakenVeina]

In your example query, you'd want to put .Batch() right before .ObserveOn(). That keeps the work of preparing batches off of the UI thread, and prevents any extra overhead from being spent on doing normal DD work under the "umbrella" of the batching.

The .Batch() operator only supports time-based batching, so if you really want it to be based on changeset sizes, you can probably setup something with .BatchIf() and like a BehaviorSubject<>....

var changeCount = new BehaviorSubject<int>(0);
changeCount.DisposeWith(_disposable);

columnFilteredObservable
    .Filter(_filterSubject) // the "Counter" filter
    .Sort(this.WhenAnyObservable(model => model.CurrentSortFilter.SortObservable), SortOptimisations.None, 500)
    .Do(changes => changeCount.Value += changes.Count)
    .BatchIf(changeCount
        .Select(changeCount => changeCount < 200))
    .Do(_ => changeCount.Value = 0)
    .ObserveOn(RxApp.MainThreadScheduler)
    .Bind(IncidentListItems)
    .Subscribe()
    .DisposeWith(_disposable);