From 9c4f7b2d9edc06cb52da8573b91248644fe6966b Mon Sep 17 00:00:00 2001
From: neuecc <ils@neue.cc>
Date: Tue, 10 Sep 2024 01:22:38 +0900
Subject: [PATCH] Dictionary FilteredView add operation adds last

---
 sandbox/ConsoleApp/Program.cs                 | 33 ++++---------------
 .../SynchronizedViewList.cs                   | 17 ++++++++--
 2 files changed, 21 insertions(+), 29 deletions(-)

diff --git a/sandbox/ConsoleApp/Program.cs b/sandbox/ConsoleApp/Program.cs
index f547f51..b293fdf 100644
--- a/sandbox/ConsoleApp/Program.cs
+++ b/sandbox/ConsoleApp/Program.cs
@@ -7,36 +7,17 @@
 using System.Collections.Generic;
 
 
+var dict = new ObservableDictionary<int, string>();
+var view = dict.CreateView(x => x).ToNotifyCollectionChanged();
+dict.Add(key: 1, value: "foo");
+dict.Add(key: 2, value: "bar");
 
-
-// Queue <-> List Synchronization
-var queue = new ObservableQueue<int>();
-
-queue.Enqueue(1);
-queue.Enqueue(10);
-queue.Enqueue(100);
-queue.Enqueue(1000);
-queue.Enqueue(10000);
-
-using var view = queue.CreateView(x => x.ToString() + "$");
-
-using var viewList = view.ToViewList();
-
-Console.WriteLine(viewList[2]); // 100$
-
-
-view.ViewChanged += View_ViewChanged;
-
-void View_ViewChanged(in SynchronizedViewChangedEventArgs<int, string> eventArgs)
+foreach (var item in view)
 {
-    if (eventArgs.Action == NotifyCollectionChangedAction.Add)
-    {
-     // eventArgs.OldItem.View.   
-    }
-
-    throw new NotImplementedException();
+    Console.WriteLine(item);
 }
 
+
 class ViewModel
 {
     public int Id { get; set; }
diff --git a/src/ObservableCollections/SynchronizedViewList.cs b/src/ObservableCollections/SynchronizedViewList.cs
index f1dc3a5..418768f 100644
--- a/src/ObservableCollections/SynchronizedViewList.cs
+++ b/src/ObservableCollections/SynchronizedViewList.cs
@@ -64,9 +64,20 @@ private void Parent_ViewChanged(in SynchronizedViewChangedEventArgs<T, TView> e)
                 case NotifyCollectionChangedAction.Add: // Add or Insert
                     if (e.IsSingleItem)
                     {
-                        var index = listView.Insert(e.NewStartingIndex, e.NewItem.View);
-                        OnCollectionChanged(e.WithNewStartingIndex(index));
-                        return;
+                        if (e.OldStartingIndex == -1)
+                        {
+                            // add operation
+                            var index = listView.Count;
+                            listView.Insert(index, e.NewItem.View);
+                            OnCollectionChanged(e.WithNewStartingIndex(index));
+                            return;
+                        }
+                        else
+                        {
+                            var index = listView.Insert(e.NewStartingIndex, e.NewItem.View);
+                            OnCollectionChanged(e.WithNewStartingIndex(index));
+                            return;
+                        }
                     }
                     else
                     {