CollectionViewSource：LiveShaping屬性不起作用

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我使用帶有LiveShaping屬性的CollectionViewSource，尤其是激活分組。問題在於更改分組屬性不能立即生效。但是，當我通過在視圖上手動調用刷新來刷新視圖時，它可以正常工作。CollectionViewSource：LiveShaping屬性不起作用

但問題是，爲什麼我在CollectionViewSource上有LiveShaping屬性，如果它們不起作用？或者我做錯了什麼？

下面是一個例子：

using System; 
using System.Collections.ObjectModel; 
using System.ComponentModel; 
using System.Runtime.CompilerServices; 
using System.Windows.Data; 

namespace ConsoleApplication6 
{ 
    class Program 
    { 
     static void Main(string[] args) 
     { 
      ObservableCollection<Test> TestList = new ObservableCollection<Test>(); 

      for (int i = 0; i < 3; i++) 
      { 
       for (int j = 0; j < 3; j++) 
       { 
        Test t = new Test() 
        { 
         Group = i.ToString(), 
         Name = (j + (i * 10)).ToString() 
        }; 

        TestList.Add(t); 
       } 
      } 

      CollectionViewSource aViewSource = new CollectionViewSource(); 
      aViewSource.Source = TestList; 

      aViewSource.IsLiveGroupingRequested = true; 
      aViewSource.GroupDescriptions.Add(new PropertyGroupDescription("Group")); 
      aViewSource.LiveGroupingProperties.Add("Group"); 

      foreach (CollectionViewGroup o in aViewSource.View.Groups) 
      { 
       Console.WriteLine(o.Name); 
       foreach (Test o2 in o.Items)Console.WriteLine("  " + o2.Name); 
      } 

      Console.WriteLine("----------------------------------------------"); 


      TestList[4].Group = "4"; 

      //aViewSource.View.Refresh(); When using this line it works. 

      foreach (CollectionViewGroup o in aViewSource.View.Groups) 
      { 
       Console.WriteLine(o.Name); 
       foreach (Test o2 in o.Items) Console.WriteLine("  " + o2.Name); 
      } 

      Console.WriteLine("----------------------------------------------"); 


      foreach (Test test in TestList) 
      { 
       Console.WriteLine("{0}: {1}", test.Group, test.Name); 
      } 


      Console.WriteLine("----------------------------------------------"); 
      Console.ReadKey(); 
     } 
    } 

    public class Test : INotifyPropertyChanged 
    { 
     public event PropertyChangedEventHandler PropertyChanged; 

     private string myName; 
     private string myGroup; 

     public string Name 
     { 
      get 
      { 
       return myName; 
      } 

      set 
      { 
       myName = value; 
       OnPropertyChanged(); 
      } 
     } 

     public string Group 
     { 
      get 
      { 
       return myGroup; 
      } 

      set 
      { 
       myGroup = value; 
       OnPropertyChanged(); 
      } 
     } 


     protected virtual void OnPropertyChanged([CallerMemberName] string propertyName_in = null) 
     { 
      PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName_in)); 
     } 

     public override string ToString() 
     { 
      return $"{Group}: {Name}"; 
     } 
    } 
}

來源

2017-04-11 msedi