使用 IReactiveDerivedList 的正确方法是用户在其中键入过滤条件

Question

我在 ReactiveList<string>

中有一个字符串的根列表

private ReactiveList<string> Items { get; set; }

和派生列表

private IReactiveDerivedList<string> _FilteredItems;
public IReactiveDerivedList<string> FilteredItems{ get => _FilteredItems; set => this.RaiseAndSetIfChanged(ref _FilteredItems, value); }

我还有一个过滤条件，当用户键入 TextBox

时会发生变化

private string _FilterTerm;
public string FilterTerm { get => _FilterTerm; set => this.RaiseAndSetIfChanged(ref _FilterTerm, value); }

最后，我在我的构造函数中使用以下内容，每次 FilterTerm 更改时 重新创建 派生列表

this.WhenAnyValue(This => This.FilterTerm).Where(filterTerm => filterTerm != null).Subscribe((filterTerm) =>
{
    FilteredItems = Items.CreateDerivedCollection(x => x, x => x.Contains(FilterTerm));
});

...我这样做是否正确，或者是否有更好的方法，因为这感觉有点像 'I could just create a new ReactiveList each time, why bother with the IReactiveDerivedList'？

更新

我找到了下面的例子，它几乎对我有用，https://janhannemann.wordpress.com/2016/10/18/reactiveui-goodies-ireactivederivedlist-filtering-2/，但它要求我向我的 ViewModel 添加一个 IsFiltered 属性，但在这种情况下，我没有使用 ViewModel，我只是使用 string!

Answer 1

如我评论中所述。 ReactiveUI 框架弃用了 ReactiveList，取而代之的是 DynamicData https://reactiveui.net/docs/handbook/collections/

如果您要在 DynamicData 中实现此目的，您将执行以下操作：

using System.Collections.ObjectModel;
using DynamicData;

public class FilteringClass
{
   private readonly ReadOnlyObservableCollection<string> _filteredItems;
   private readonly SourceList<string> _items = new SourceList<string>();
   private string _filterTerm;

   public FilteringClass(IEnumerable<string> items)
   {
      var filterTermChanged = this.WhenAnyValue(x => x.FilterTerm);
      _items.AddRange(items);
      _items.Connect()
         // This will update your output list whenever FilterTerm changes.
         .AutoRefreshOnObservable(_ => filterTermChanged)
         // This is similar to a Where() statement.
         .Filter(x => FilterTerm == null || x.Contains(FilterTerm))
         // SourceList is thread safe, this will make your output list only be updated on the main thread.
         .ObserveOn(RxApp.MainThreadScheduler)
         // This will make the FilteredItem's be updated with our data.
         .Bind(out _filteredItems)
         // This is a observable, so Subscribe to start the goodness.
         .Subscribe();

   }

   public string FilterTerm
   {
      get => _filterTerm;
      set => RaiseAndSetIfChanged(ref _filterTerm, value);
   }

   public ReadOnlyObservableCollection<string> FilteredItems => _filteredItems;
}

使用 IReactiveDerivedList 的正确方法是用户在其中键入过滤条件

Correct way to use IReactiveDerivedList as a user types a filter term in

c#

reactive-programming

reactiveui