Fix UI flickering

See #350

Wox.Plugin/Result.cs

@@ -42,12 +42,22 @@ namespace Wox.Plugin
         /// </summary>
         public string PluginDirectory { get; internal set; }
 
-        public new bool Equals(object obj)
+        public override bool Equals(object obj)
         {
-            if (obj == null || !(obj is Result)) return false;
+            Result r = obj as Result;
+            if (r != null)
+            {
+                return string.Equals(r.Title, Title) && string.Equals(r.SubTitle, SubTitle);
+            }
+            else
+            {
+                return false;
+            }
+        }
 
-            Result r = (Result)obj;
+        public override int GetHashCode()
-            return r.Title == Title && r.SubTitle == SubTitle;
+        {
+            return (Title?.GetHashCode() ?? 0) ^ (SubTitle?.GetHashCode() ?? 0);
         }
 
         public override string ToString()

Wox/MainWindow.xaml.cs

@@ -441,36 +441,33 @@ namespace Wox
 
         private void TbQuery_OnTextChanged(object sender, TextChangedEventArgs e)
         {
+            
             if (ignoreTextChange) { ignoreTextChange = false; return; }
 
-            toolTip.IsOpen = false;
+            if (!string.IsNullOrEmpty(tbQuery.Text.Trim()))
-            pnlResult.Dirty = true;
-            if (IsInContextMenuMode)
             {
-                QueryContextMenu();
+                toolTip.IsOpen = false;
-                return;
+                if (IsInContextMenuMode)
-            }
-
-            queryHasReturn = false;
-
-            Dispatcher.DelayInvoke("ClearResults", () =>
-            {
-                // Delay the invocation of clear method of pnlResult, minimize the time-span between clear results and add new results. 
-                // So this will reduce splash issues. After waiting 100ms, if there still no results added, we
-                // must clear the result. otherwise, it will be confused why the query changed, but the results
-                // didn't.
-                if (pnlResult.Dirty) pnlResult.Clear();
-            }, TimeSpan.FromMilliseconds(100));
-            Query(tbQuery.Text);
-            Dispatcher.DelayInvoke("ShowProgressbar", () =>
-            {
-                if (!string.IsNullOrEmpty(tbQuery.Text.Trim()) && tbQuery.Text != lastQuery && !queryHasReturn)
                 {
-                    StartProgress();
+                    QueryContextMenu();
+                    return;
                 }
-            }, TimeSpan.FromMilliseconds(150));
+
-            //reset query history index after user start new query
+                Query(tbQuery.Text);
-            ResetQueryHistoryIndex();
+                Dispatcher.DelayInvoke("ShowProgressbar", () =>
+                {
+                    if (!string.IsNullOrEmpty(tbQuery.Text.Trim()) && tbQuery.Text != lastQuery && !queryHasReturn)
+                    {
+                        StartProgress();
+                    }
+                }, TimeSpan.FromMilliseconds(150));
+                //reset query history index after user start new query
+                ResetQueryHistoryIndex();
+            }
+            else
+            {
+                pnlResult.Clear();
+            }
         }
 
         private void ResetQueryHistoryIndex()
@@ -720,7 +717,6 @@ namespace Wox
             if (history != null)
             {
                 ChangeQueryText(history.Query, true);
-                pnlResult.Dirty = true;
                 var executeQueryHistoryTitle = GetTranslation("executeQuery");
                 var lastExecuteTime = GetTranslation("lastExecuteTime");
                 UpdateResultViewInternal(new List<Result>()

Wox/ResultPanel.xaml.cs

@@ -1,20 +1,27 @@
 using System;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Diagnostics;
 using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Input;
 using System.Windows.Media;
+using System.Linq;
+using System.Runtime.Remoting.Contexts;
 using Wox.Core.UserSettings;
 using Wox.Plugin;
 using Wox.Storage;
 
 namespace Wox
 {
+    [Synchronization]
     public partial class ResultPanel : UserControl
     {
         public event Action<Result> LeftMouseClickEvent;
         public event Action<Result> RightMouseClickEvent;
         public event Action<Result, IDataObject, DragEventArgs> ItemDropEvent;
+        private readonly ObservableCollection<Result> _results; //todo, for better performance, override the default linear search
+        private readonly object _resultsUpdateLock = new object();
 
         protected virtual void OnRightMouseClick(Result result)
         {
@@ -28,36 +35,69 @@ namespace Wox
             if (handler != null) handler(result);
         }
 
-        public bool Dirty { get; set; }
 
         public int MaxResultsToShow { get { return UserSettingStorage.Instance.MaxResultsToShow * 50; } }
 
-        public void AddResults(List<Result> results)
+        public void AddResults(List<Result> newResults)
         {
-            if (Dirty)
+            if (newResults != null && newResults.Count > 0)
             {
-                Dirty = false;
+                lock (_resultsUpdateLock)
-                lbResults.Items.Clear();
-            }
-            foreach (var result in results)
-            {
-                int position = 0;
-                if (IsTopMostResult(result))
                 {
-                    result.Score = int.MaxValue;
+                    var pluginId = newResults[0].PluginID;
-                }
+                    var actionKeyword = newResults[0].OriginQuery.ActionKeyword;
-                else
+                    List<Result> oldResults;
-                {
+                    if (string.IsNullOrEmpty(actionKeyword))
-                    if (result.Score >= int.MaxValue)
                     {
-                        result.Score = int.MaxValue - 1;
+                        oldResults = _results.Where(r => r.PluginID == pluginId).ToList();
                     }
-                    position = GetInsertLocation(result.Score);
+                    else
+                    {
+                        oldResults = _results.ToList();
+                    }
+                    // intersection of A (old results) and B (new newResults)
+                    var intersection = oldResults.Intersect(newResults).ToList();
+
+                    // remove result of relative complement of B in A
+                    foreach (var result in oldResults.Except(intersection))
+                    {
+                        _results.Remove(result);
+                    }
+
+                    // update scores
+                    foreach (var result in newResults)
+                    {
+                        if (IsTopMostResult(result))
+                        {
+                            result.Score = int.MaxValue;
+                        }
+                    }
+
+                    // update index for result in intersection of A and B
+                    foreach (var result in intersection)
+                    {
+                        int oldIndex = _results.IndexOf(result);
+                        int oldScore = _results[oldIndex].Score;
+                        if (result.Score != oldScore)
+                        {
+                            int newIndex = InsertIndexOf(result.Score);
+                            if (newIndex != oldIndex)
+                            {
+                                _results.Move(oldIndex, newIndex);
+                            }
+                        }
+                    }
+
+                    // insert result in relative complement of A in B
+                    foreach (var result in newResults.Except(intersection))
+                    {
+                        int newIndex = InsertIndexOf(result.Score);
+                        _results.Insert(newIndex, result);
+                    }
+                    lbResults.Margin = lbResults.Items.Count > 0 ? new Thickness { Top = 8 } : new Thickness { Top = 0 };
+                    SelectFirst();
                 }
-                lbResults.Items.Insert(position, result);
             }
-            lbResults.Margin = lbResults.Items.Count > 0 ? new Thickness { Top = 8 } : new Thickness { Top = 0 };
-            SelectFirst();
         }
 
         private bool IsTopMostResult(Result result)
@@ -65,33 +105,18 @@ namespace Wox
             return TopMostRecordStorage.Instance.IsTopMost(result);
         }
 
-        private int GetInsertLocation(int currentScore)
+        private int InsertIndexOf(int newScore)
         {
-            int location = lbResults.Items.Count;
+            int index = 0;
-            if (lbResults.Items.Count == 0) return 0;
+            for (; index < lbResults.Items.Count; index++)
-            if (currentScore > ((Result)lbResults.Items[0]).Score) return 0;
-
-            for (int index = 1; index < lbResults.Items.Count; index++)
             {
-                Result next = lbResults.Items[index] as Result;
+                Result result = lbResults.Items[index] as Result;
-                Result prev = lbResults.Items[index - 1] as Result;
+                if (newScore > result?.Score)
-                if (next != null && prev != null)
                 {
-                    if ((currentScore >= next.Score && currentScore <= prev.Score))
+                    break;
-                    {
-                        if (currentScore == next.Score)
-                        {
-                            location = index + 1;
-                        }
-                        else
-                        {
-                            location = index;
-                        }
-                    }
                 }
             }
-
+            return index;
-            return location;
         }
 
         public void SelectNext()
@@ -211,12 +236,17 @@ namespace Wox
         public ResultPanel()
         {
             InitializeComponent();
+            _results = new ObservableCollection<Result>();
+            lbResults.ItemsSource = _results;
         }
 
         public void Clear()
         {
-            lbResults.Items.Clear();
+            lock (_resultsUpdateLock)
-            lbResults.Margin = new Thickness { Top = 0 };
+            {
+                _results.Clear();
+                lbResults.Margin = new Thickness { Top = 0 };
+            }
         }
 
         private void lbResults_SelectionChanged(object sender, SelectionChangedEventArgs e)