Buffer PropertyChanged Events

Question

我有一個wpf應用程序，所有viewModel都繼承自實現INotifyPropertyChanged的NotifyPropertyChangeClass類（見下文）。

我想限制發送到視圖的通知，以避免由於發送太多通知而導致滯後。 到目前爲止，我所實現的目標是使用反應擴展方法Sample來延遲每個屬性。

問題在於，Gui在throttlingPeriod後期被刷新了。它會覺得更適應有在這樣的週期始提出了第一個事件：

NotifyPropertyChangeClass的代碼：

using System; 
using System.ComponentModel; 
using System.Reactive.Linq; 

namespace MyNameSpace 
{ 
    public class NotifyPropertyChangeClass : INotifyPropertyChanged 
    { 
     public NotifyPropertyChangeClass(int throttlingPeriod) 
     { 
      var obs = Observable.FromEventPattern<PropertyChangedEventHandler, PropertyChangedEventArgs>(
       h => this.privatePropertyChanged += h, h => this.privatePropertyChanged -= h); 
      var groupedByName = obs.Select(o => o.EventArgs.PropertyName).GroupBy(x => x).SelectMany(o => o.Sample(TimeSpan.FromMilliseconds(throttlingPeriod))); 
      groupedByName.Subscribe(o => 
      { 
       PropertyChangedEventHandler handler = PropertyChanged; 
       if (handler != null) 
        handler(this, new PropertyChangedEventArgs(o)); 
      }); 
     } 
     public event PropertyChangedEventHandler PropertyChanged; 
     private event PropertyChangedEventHandler privatePropertyChanged; 

     protected virtual void OnPropertyChanged(string propertyName) 
     { 
      PropertyChangedEventHandler handler = privatePropertyChanged; 
      if (handler != null) 
       handler(this, new PropertyChangedEventArgs(propertyName)); 
     } 
    } 
} 

我如何能實現我想要什麼？

Answer 1

我沒有試過，但你可以試試這個：

using System; 
using System.ComponentModel; 
using System.Reactive.Linq; 

namespace MyNameSpace 
{ 
    public class NotifyPropertyChangeClass : INotifyPropertyChanged 
    { 
     private bool _isThrottling = false; 

     public NotifyPropertyChangeClass(int throttlingPeriod) 
     { 
      var obs = Observable.FromEventPattern<PropertyChangedEventHandler, PropertyChangedEventArgs>(
       h => this.privatePropertyChanged += h, h => this.privatePropertyChanged -= h); 
      var groupedByName = obs.Select(o => o.EventArgs.PropertyName).GroupBy(x => x).SelectMany(o => o.Sample(TimeSpan.FromMilliseconds(throttlingPeriod))); 
      groupedByName.Subscribe(o => 
      { 
       PropertyChangedEventHandler handler = PropertyChanged; 
       if (handler != null) 
        handler(this, new PropertyChangedEventArgs(o)); 
       _isThrottling = false; 
      }); 
     } 
     public event PropertyChangedEventHandler PropertyChanged; 
     private event PropertyChangedEventHandler privatePropertyChanged; 

     protected virtual void OnPropertyChanged(string propertyName) 
     { 
      // Will fire the first time, the event is raised 
      if (!_isThrottling) 
      { 
       PropertyChangedEventHandler handler = PropertyChanged; 
       if (handler != null) 
        handler(this, new PropertyChangedEventArgs(o)); 
      } 

      // Setting to true here will suppress raising the public event 
      // for every subsequent call, until the event is raised 
      // by the observable pattern and the flag is set to false again. 
      _isThrottling = true; 

      // Will always be raised 
      PropertyChangedEventHandler handler = privatePropertyChanged; 
      if (handler != null) 
       handler(this, new PropertyChangedEventArgs(propertyName)); 
     } 
    } 
}