Use DynamicData as resultcollection

Flow.Launcher/ResultListBox.axaml

@@ -12,12 +12,12 @@
         SelectedIndex="{Binding SelectedIndex, Mode=TwoWay}"
         SelectedItem="{Binding SelectedItem, Mode=TwoWay}"
         SelectionMode="AlwaysSelected"
-        AutoScrollToSelectedItem="False"
+        AutoScrollToSelectedItem="True"
         IsVisible="{Binding Visibility}"
         MaxHeight="{Binding MaxHeight}">
         <ListBox.ItemTemplate>
             <DataTemplate>
-                <Button HorizontalAlignment="Stretch" Height="40">
+                <Button HorizontalAlignment="Stretch" Height="40" x:DataType="vm:ResultViewModel">
                     <Button.Template>
                         <ControlTemplate>
                             <ContentPresenter Content="{TemplateBinding Button.Content}" />
@@ -78,7 +78,7 @@
                                         Margin="0,0,0,0"
                                         HorizontalAlignment="Center"
                                         IsHitTestVisible="False"
-                                        Source="{Binding Image^, FallbackValue={Binding DefaultImage}, TargetNullValue={x:Null}}"
+                                        Source="{Binding Image^, FallbackValue={Binding DefaultImage}}"
                                         Stretch="Uniform"
                                         IsVisible="{Binding ShowIcon}">
                                     </Image>

Flow.Launcher/ViewModels/ResultViewModel.cs

@@ -239,10 +239,7 @@ namespace Flow.Launcher.ViewModel
         {
             get
             {
-                if (Result.ProgressBar == null)
-                    return 0;
-
-                return Result.ProgressBar.Value;
+                return Result.ProgressBar ?? 0;
             }
         }
 

Flow.Launcher/ViewModels/ResultsViewModel.cs

@@ -1,14 +1,22 @@
-using Flow.Launcher.Infrastructure.UserSettings;
+using System;
+using Flow.Launcher.Infrastructure.UserSettings;
 using Flow.Launcher.Plugin;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Collections.Specialized;
 using System.Linq;
+using System.Reactive.Disposables;
+using System.Reactive.Linq;
+using System.Runtime.CompilerServices;
 using System.Threading;
 using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Data;
 using System.Windows.Documents;
 using System.Windows.Input;
+using Avalonia.ReactiveUI;
+using DynamicData;
+using DynamicData.Binding;
 
 namespace Flow.Launcher.ViewModel
 {
@@ -16,16 +24,40 @@ namespace Flow.Launcher.ViewModel
     {
         #region Private Fields
 
-        public ResultCollection Results { get; }
+        private ReadOnlyObservableCollection<ResultViewModel> _results;
+        public ReadOnlyObservableCollection<ResultViewModel> Results => _results;
+
+        private SourceList<Result> _resultsCache = new();
 
         private readonly object _collectionLock = new object();
         private readonly Settings _settings;
         private int MaxResults => _settings?.MaxResultsToShow ?? 6;
 
+        public void MoveIndex(int diff)
+        {
+            if (Results.Count == 0)
+            {
+                SelectedIndex = -1;
+                return;
+            }
+
+            SelectedIndex = Mod(SelectedIndex + diff, Results.Count);
+            return;
+
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            int Mod(int x, int m) => (x % m + m) % m;
+        }
+
+        private IDisposable _resultsSubscription;
+
         public ResultsViewModel()
         {
-            Results = new ResultCollection();
-            BindingOperations.EnableCollectionSynchronization(Results, _collectionLock);
+            _resultsSubscription = _resultsCache.Connect()
+                .Sort(SortExpressionComparer<Result>.Descending(r => r.Score))
+                .Transform(r => new ResultViewModel(r, _settings))
+                .Bind(out _results)
+                .Do(_ => MoveIndex(-SelectedIndex))
+                .Subscribe();
         }
 
         public ResultsViewModel(Settings settings) : this()
@@ -59,21 +91,6 @@ namespace Flow.Launcher.ViewModel
 
         #region Private Methods
 
-        private int InsertIndexOf(int newScore, IList<ResultViewModel> list)
-        {
-            int index = 0;
-            for (; index < list.Count; index++)
-            {
-                var result = list[index];
-                if (newScore > result.Result.Score)
-                {
-                    break;
-                }
-            }
-
-            return index;
-        }
-
         private int NewIndex(int i)
         {
             var n = Results.Count;
@@ -120,20 +137,23 @@ namespace Flow.Launcher.ViewModel
 
         public void Clear()
         {
-            lock (_collectionLock)
-                Results.RemoveAll();
+            _resultsCache.Clear();
         }
 
         public void KeepResultsFor(PluginMetadata metadata)
         {
-            lock (_collectionLock)
-                Results.Update(Results.Where(r => r.Result.PluginID == metadata.ID).ToList());
+            _resultsCache.Edit(list =>
+            {
+                list.Remove(list.Where(x => x.PluginID != metadata.ID));
+            });
         }
 
         public void KeepResultsExcept(PluginMetadata metadata)
         {
-            lock (_collectionLock)
-                Results.Update(Results.Where(r => r.Result.PluginID != metadata.ID).ToList());
+            _resultsCache.Edit(list =>
+            {
+                list.Remove(list.Where(x => x.PluginID == metadata.ID));
+            });
         }
 
         /// <summary>
@@ -141,9 +161,7 @@ namespace Flow.Launcher.ViewModel
         /// </summary>
         public void AddResults(List<Result> newRawResults, string resultId)
         {
-            var newResults = NewResults(newRawResults, resultId);
-
-            UpdateResults(newResults);
+            NewResults(newRawResults, resultId);
         }
 
         /// <summary>
@@ -151,59 +169,30 @@ namespace Flow.Launcher.ViewModel
         /// </summary>
         public void AddResults(IEnumerable<ResultsForUpdate> resultsForUpdates, CancellationToken token)
         {
-            var newResults = NewResults(resultsForUpdates);
-
-            if (token.IsCancellationRequested)
-                return;
-
-            UpdateResults(newResults, token);
+            NewResults(resultsForUpdates);
         }
 
-        private void UpdateResults(List<ResultViewModel> newResults, CancellationToken token = default)
+
+        private void NewResults(IReadOnlyCollection<Result> newRawResults, string resultId)
         {
-            lock (_collectionLock)
+            _resultsCache.Edit(list =>
             {
-                // update UI in one run, so it can avoid UI flickering
-                Results.Update(newResults, token);
-                if (Results.Any())
-                    SelectedItem = Results[0];
-            }
+                list.Remove(list.Where(x => x.PluginID == resultId).ToList());
+                list.AddRange(newRawResults);
+            });
+        }
 
-            switch (Visibility)
+        private void NewResults(IEnumerable<ResultsForUpdate> resultsForUpdates)
+        {
+            _resultsCache.Edit(list =>
             {
-                case false when Results.Count > 0:
-                    SelectedIndex = 0;
-                    Visibility = true;
-                    break;
-                case true when Results.Count == 0:
-                    Visibility = false;
-                    break;
-            }
-        }
+                list.Remove(list.Where(x => resultsForUpdates.Any(r => r.ID == x.PluginID)).ToList());
 
-        private List<ResultViewModel> NewResults(List<Result> newRawResults, string resultId)
-        {
-            if (newRawResults.Count == 0)
-                return Results;
-
-
-            var newResults = newRawResults.Select(r => new ResultViewModel(r, _settings));
-
-            return Results.Where(r => r.Result.PluginID != resultId)
-                .Concat(newResults)
-                .OrderByDescending(r => r.Result.Score)
-                .ToList();
-        }
-
-        private List<ResultViewModel> NewResults(IEnumerable<ResultsForUpdate> resultsForUpdates)
-        {
-            if (!resultsForUpdates.Any())
-                return Results;
-
-            return Results.Where(r => r != null && !resultsForUpdates.Any(u => u.ID == r.Result.PluginID))
-                .Concat(resultsForUpdates.SelectMany(u => u.Results, (u, r) => new ResultViewModel(r, _settings)))
-                .OrderByDescending(rv => rv.Result.Score)
-                .ToList();
+                foreach (var resultsForUpdate in resultsForUpdates)
+                {
+                    list.AddRange(resultsForUpdate.Results);
+                }
+            });
         }
 
         #endregion
@@ -240,85 +229,5 @@ namespace Flow.Launcher.ViewModel
         }
 
         #endregion
-
-        public class ResultCollection : List<ResultViewModel>, INotifyCollectionChanged
-        {
-            private long editTime = 0;
-
-            private CancellationToken _token;
-
-            public event NotifyCollectionChangedEventHandler CollectionChanged;
-
-
-            protected void OnCollectionChanged(NotifyCollectionChangedEventArgs e)
-            {
-                CollectionChanged?.Invoke(this, e);
-            }
-
-            public void BulkAddAll(List<ResultViewModel> resultViews)
-            {
-                AddRange(resultViews);
-
-                // can return because the list will be cleared next time updated, which include a reset event
-                if (_token.IsCancellationRequested)
-                    return;
-
-                // manually update event
-                // wpf use DirectX / double buffered already, so just reset all won't cause ui flickering
-                OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
-            }
-
-            private void AddAll(List<ResultViewModel> Items)
-            {
-                for (int i = 0; i < Items.Count; i++)
-                {
-                    var item = Items[i];
-                    if (_token.IsCancellationRequested)
-                        return;
-                    Add(item);
-                    OnCollectionChanged(
-                        new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, item, i));
-                }
-            }
-
-            public void RemoveAll(int Capacity = 512)
-            {
-                Clear();
-                if (this.Capacity > 8000 && Capacity < this.Capacity)
-                    this.Capacity = Capacity;
-
-                OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
-            }
-
-            /// <summary>
-            /// Update the results collection with new results, try to keep identical results
-            /// </summary>
-            /// <param name="newItems"></param>
-            public void Update(List<ResultViewModel> newItems, CancellationToken token = default)
-            {
-                _token = token;
-                if (Count == 0 && newItems.Count == 0 || _token.IsCancellationRequested)
-                    return;
-
-                if (editTime < 10 || newItems.Count < 30)
-                {
-                    if (Count != 0) RemoveAll(newItems.Count);
-                    AddAll(newItems);
-                    editTime++;
-                    return;
-                }
-                else
-                {
-                    Clear();
-                    BulkAddAll(newItems);
-                    if (Capacity > 8000 && newItems.Count < 3000)
-                    {
-                        Capacity = newItems.Count;
-                    }
-
-                    editTime++;
-                }
-            }
-        }
     }
 }