WPF 對ObservableCollection 進行排序

通過C＃對ObservableCollection 進行排序

方法一

public static void MySort<TSource,TKey>(this ObservableCollection<TSource> observableCollection, Func<TSource, TKey> keySelector)
    {
        var a = observableCollection.OrderBy(keySelector).ToList();
        observableCollection.Clear();
        foreach(var b in a)
        {
            observableCollection.Add(b);
        }
    }

方法二

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Collections.Specialized;
using System.Linq;

namespace ConsoleApp4
{
  using static Console;

  public class SortableObservableCollection<T> : ObservableCollection<T>
  {
    public Func<T, object> SortingSelector { get; set; }
    public bool Descending { get; set; }
    protected override void OnCollectionChanged(NotifyCollectionChangedEventArgs e)
    {
      base.OnCollectionChanged(e);
      if (SortingSelector == null 
          || e.Action == NotifyCollectionChangedAction.Remove
          || e.Action == NotifyCollectionChangedAction.Reset)
        return;

      var query = this
        .Select((item, index) => (Item: item, Index: index));
      query = Descending
        ? query.OrderBy(tuple => SortingSelector(tuple.Item))
        : query.OrderByDescending(tuple => SortingSelector(tuple.Item));

      var map = query.Select((tuple, index) => (OldIndex:tuple.Index, NewIndex:index))
       .Where(o => o.OldIndex != o.NewIndex);

      using (var enumerator = map.GetEnumerator())
       if (enumerator.MoveNext())
          Move(enumerator.Current.OldIndex, enumerator.Current.NewIndex);


    }
  }


  //USAGE
  class Program
  {
    static void Main(string[] args)
    {
      var xx = new SortableObservableCollection<int>() { SortingSelector = i => i };
      xx.CollectionChanged += (sender, e) =>
       WriteLine($"action: {e.Action}, oldIndex:{e.OldStartingIndex},"
         + " newIndex:{e.NewStartingIndex}, newValue: {xx[e.NewStartingIndex]}");

      xx.Add(10);
      xx.Add(8);
      xx.Add(45);
      xx.Add(0);
      xx.Add(100);
      xx.Add(-800);
      xx.Add(4857);
      xx.Add(-1);

      foreach (var item in xx)
        Write($"{item}, ");
    }
  }
}

輸出：

action: Add, oldIndex:-1, newIndex:0, newValue: 10
action: Add, oldIndex:-1, newIndex:1, newValue: 8
action: Move, oldIndex:1, newIndex:0, newValue: 8
action: Add, oldIndex:-1, newIndex:2, newValue: 45
action: Add, oldIndex:-1, newIndex:3, newValue: 0
action: Move, oldIndex:3, newIndex:0, newValue: 0
action: Add, oldIndex:-1, newIndex:4, newValue: 100
action: Add, oldIndex:-1, newIndex:5, newValue: -800
action: Move, oldIndex:5, newIndex:0, newValue: -800
action: Add, oldIndex:-1, newIndex:6, newValue: 4857
action: Add, oldIndex:-1, newIndex:7, newValue: -1
action: Move, oldIndex:7, newIndex:1, newValue: -1
-800, -1, 0, 8, 10, 45, 100, 4857,

在ObservableCollection上使用CollectionViewSource進行列表框實時排序

<ListBox x:Name="EquipmentList" 
         ItemsSource="{StaticResource SortedEquipmentList}" 
         ...
         />

<CollectionViewSource x:Key="SortedEquipmentList" 
                      Source="{Binding EquipmentList.View}" 
                      IsLiveSortingRequested="True">
    <CollectionViewSource.SortDescriptions>
        <scm:SortDescription PropertyName="Description" Direction="Ascending"/>
    </CollectionViewSource.SortDescriptions>
    <CollectionViewSource.LiveSortingProperties>
        <clr:String>Description</clr:String>
    </CollectionViewSource.LiveSortingProperties>
</CollectionViewSource>