From 0050439932a9c89a6c87352f27568c0c460419e4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=81d=C3=A1m=20Kov=C3=A1cs?= <kovacsadam07@outlook.hu>
Date: Tue, 5 Sep 2023 11:11:15 +0200
Subject: [PATCH] Fix ItemsControl not handling collection changed

---
 .../TerminalUI/Controls/ItemsControl.cs       | 21 +++++++++++++++++--
 src/Library/TerminalUI/Controls/ListView.cs   | 15 +++++++++----
 2 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/src/Library/TerminalUI/Controls/ItemsControl.cs b/src/Library/TerminalUI/Controls/ItemsControl.cs
index 71039fa..d9e50b8 100644
--- a/src/Library/TerminalUI/Controls/ItemsControl.cs
+++ b/src/Library/TerminalUI/Controls/ItemsControl.cs
@@ -1,4 +1,5 @@
 using System.Collections.ObjectModel;
+using System.Collections.Specialized;
 using ObservableComputations;
 using PropertyChanged.SourceGenerator;
 using TerminalUI.Models;
@@ -27,6 +28,10 @@ public sealed partial class ItemsControl<TDataContext, TItem>
         set
         {
             if (_itemsSource == value) return;
+            
+            if(_itemsSource is INotifyCollectionChanged notifyCollectionChanged)
+                notifyCollectionChanged.CollectionChanged -= SourceCollectionChanged;
+            
             _itemsSource = value;
 
             foreach (var disposable in _itemsDisposables)
@@ -39,17 +44,25 @@ public sealed partial class ItemsControl<TDataContext, TItem>
             if (_itemsSource is ObservableCollection<TItem> observableDeclarative)
             {
                 var consumer = new OcConsumer();
-                _children = observableDeclarative
+                var children = observableDeclarative
                     .Selecting(i => CreateItem(i))
                     .For(consumer);
+                
+                children.CollectionChanged += SourceCollectionChanged;
+                _children = children;
+                
                 _itemsDisposables.Add(consumer);
             }
             else if (_itemsSource is ReadOnlyObservableCollection<TItem> readOnlyObservableDeclarative)
             {
                 var consumer = new OcConsumer();
-                _children = readOnlyObservableDeclarative
+                var children = readOnlyObservableDeclarative
                     .Selecting(i => CreateItem(i))
                     .For(consumer);
+                
+                children.CollectionChanged += SourceCollectionChanged;
+                _children = children;
+                
                 _itemsDisposables.Add(consumer);
             }
             else if (_itemsSource is ICollection<TItem> collection)
@@ -78,6 +91,10 @@ public sealed partial class ItemsControl<TDataContext, TItem>
         RerenderProperties.Add(nameof(Orientation));
     }
 
+    private void SourceCollectionChanged(object? sender, NotifyCollectionChangedEventArgs e) => RequestRerenderForThis();
+
+    private void RequestRerenderForThis() 
+        => ApplicationContext?.RenderEngine.RequestRerender(this);
 
     protected override Size CalculateSize()
     {
diff --git a/src/Library/TerminalUI/Controls/ListView.cs b/src/Library/TerminalUI/Controls/ListView.cs
index 19a8fae..7916f30 100644
--- a/src/Library/TerminalUI/Controls/ListView.cs
+++ b/src/Library/TerminalUI/Controls/ListView.cs
@@ -76,6 +76,10 @@ public sealed partial class ListView<TDataContext, TItem> : View<ListView<TDataC
         set
         {
             if (_itemsSource == value) return;
+
+            if (_itemsSource is INotifyCollectionChanged notifyCollectionChanged)
+                notifyCollectionChanged.CollectionChanged -= SourceCollectionChanged;
+
             _itemsSource = value;
 
             foreach (var disposable in _itemsDisposables)
@@ -87,15 +91,13 @@ public sealed partial class ListView<TDataContext, TItem> : View<ListView<TDataC
 
             if (_itemsSource is ObservableCollection<TItem> observableDeclarative)
             {
-                ((INotifyCollectionChanged) observableDeclarative).CollectionChanged +=
-                    (_, _) => ApplicationContext?.RenderEngine.RequestRerender(this);
+                ((INotifyCollectionChanged) observableDeclarative).CollectionChanged += SourceCollectionChanged;
 
                 _getItems = () => observableDeclarative;
             }
             else if (_itemsSource is ReadOnlyObservableCollection<TItem> readOnlyObservableDeclarative)
             {
-                ((INotifyCollectionChanged) readOnlyObservableDeclarative).CollectionChanged +=
-                    (_, _) => ApplicationContext?.RenderEngine.RequestRerender(this);
+                ((INotifyCollectionChanged) readOnlyObservableDeclarative).CollectionChanged += SourceCollectionChanged;
 
                 _getItems = () => readOnlyObservableDeclarative;
             }
@@ -135,6 +137,11 @@ public sealed partial class ListView<TDataContext, TItem> : View<ListView<TDataC
         RerenderProperties.Add(nameof(Orientation));
     }
 
+    private void SourceCollectionChanged(object? sender, NotifyCollectionChangedEventArgs e) => RequestRerenderForThis();
+
+    private void RequestRerenderForThis()
+        => ApplicationContext?.RenderEngine.RequestRerender(this);
+
     protected override Size CalculateSize()
     {
         InstantiateItemViews();