Integration with ReactiveUI

I have released DynamicData.ReactiveUI which is a very simple adaptor layer to assist with binding dynamic data observables with reactiveui’s ReactiveList object.

Install from Nuget

If you are not familiar with dynamic data and what it enables I suggest:

1. Go through previous posts in the blog
2. Download the example wpf app from github

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To cut to the chase, here’s an example. The code takes existing in-memory trade objects, transforms them into a view model proxy and updates the target reactive list object with the resulting change sets. It also pre-filters the data with live trades, applies a user entered filter, orders the resulting data and disposes the proxy when no longer required. Phew – all that in effectively one line of code.

I did the same example without using Reactive UI code see Trading Example Part 3. Integrate with UI where I have explained the code in greater detail

    public class RxUiViewer : ReactiveObject, IDisposable
    {
       //this is the target list which we will populate from the dynamic data stream
        private readonly ReactiveList<TradeProxy> _data = new ReactiveList<TradeProxy>();
        //the filter controller is used to inject filtering into a observable
        private readonly FilterController<Trade> _filter = new FilterController<Trade>();
        private readonly IDisposable _cleanUp;
        private string _searchText;

        public RxUiViewer(ITradeService tradeService)
        {
            //Change the filter when the user entered search text changes
            var filterApplier = this.WhenAnyValue(x => x.SearchText)
                .Throttle(TimeSpan.FromMilliseconds(250))
                .Subscribe(_ => ApplyFilter());
           
            ApplyFilter();

            var loader = tradeService.Trades
                .Connect(trade => trade.Status == TradeStatus.Live) //prefilter live trades only
                .Filter(_filter)    // apply user filter
                   //if targetting Net4 or Net45 platform can use parallelisation for transforms 'cause it's quicker
                .Transform(trade => new TradeProxy(trade), new ParallelisationOptions(ParallelType.Ordered, 5))
                .Sort(SortExpressionComparer<TradeProxy>.Descending(t => t.Timestamp), SortOptimisations.ComparesImmutableValuesOnly)
                .ObserveOn(RxApp.MainThreadScheduler)
                .Bind(_data)        //bind the results to the ReactiveList 
                .DisposeMany()      //since TradeProxy is disposable dispose when no longer required
                .Subscribe();

            _cleanUp = new CompositeDisposable(loader, _filter, filterApplier);
        }

        private void ApplyFilter()
        {
            if (string.IsNullOrEmpty(SearchText))
            {
                _filter.ChangeToIncludeAll();
            }
            else
            {
                _filter.Change(t => t.CurrencyPair.Contains(SearchText, StringComparison.OrdinalIgnoreCase) ||
                                    t.Customer.Contains(SearchText, StringComparison.OrdinalIgnoreCase));
            }
        }

        public string SearchText
        {
            get { return _searchText; }
            set { this.RaiseAndSetIfChanged(ref _searchText, value); }
        }

        public IReadOnlyReactiveList<TradeProxy> Data
        {
            get { return _data; }
        }

        public void Dispose()
        {
            _cleanUp.Dispose();
        }
    }

coupled with a little xaml can produce this

Very little code, but a very powerful example,

• c#
• Dynamic Data
• dynamic filter
• DynamicData
• Reactive
• ReactiveUI
• rx
• Trading