使用System.Reactive观察ObservableCollection中的项目的PropertyChanged

我有：

public class Vm { private ObservableCollection _things; public ObservableCollection Things { get { return _things ?? (_things = new ObservableCollection()); } } } 

和

 public class Thing :INotifyPropertyChanged { private string _value; public string Value { get { return _value; } set { if (value == _value) return; _value = value; OnPropertyChanged(); } } public event PropertyChangedEventHandler PropertyChanged; [NotifyPropertyChangedInvocator] protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null) { PropertyChangedEventHandler handler = PropertyChanged; if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName)); } } 

我想观察ObservableCollection中所有项目的PropertyChanges

rx是否适合这个？

观察者如何在这种情况下接线？ （我可以发布一些你尝试过的东西，但我认为它不会增加太多）

Answer 1

Rx是一个完美的契合，我不会称之为重新发明轮子！

考虑这个简单的扩展方法，用于将属性更改事件转换为可观察流：

 public static class NotifyPropertyChangedExtensions { public static IObservable WhenPropertyChanged(this NotifyPropertyChanged notifyPropertyChanged) { return Observable.FromEvent( ev => notifyPropertyChanged.PropertyChanged += ev, ev => notifyPropertyChanged.PropertyChanged -= ev); } } 

在您的视图模型中，您只需合并所有单个可观察的属性更改流：

 public class VM { readonly SerialDisposable subscription; public VM() { subscription = new SerialDisposable(); Things = new ObservableCollection(); Things.CollectionChanged += ThingsCollectionChanged; } void ThingsCollectionChanged(object sender, NotifyCollectionChangedEventArgs e) { subscription.Disposable = Things.Select(t => t.WhenPropertyChanged()) .Merge() .Subscribe(OnThingPropertyChanged); } void OnThingPropertyChanged(PropertyChangedEventArgs obj) { //ToDo! } public ObservableCollection Things { get; private set; } }