Performance improvement for filtered collection (#441)

* Remove LINQ * increment version number
runceel · Sep 23, 2023 · 9424c75 · 9424c75
1 parent 9d4f78a
commit 9424c75
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Showing 2 changed files with 11 additions and 2 deletions.
diff --git a/Source/Directory.Build.props b/Source/Directory.Build.props
@@ -1,7 +1,7 @@
 <Project>
   <PropertyGroup>
     <RootNamespace>Reactive.Bindings</RootNamespace>
-    <Version>9.3.1</Version>
+    <Version>9.3.2</Version>
     <Authors>neuecc xin9le okazuki</Authors>
     <PackageProjectUrl>https://github.com/runceel/ReactiveProperty</PackageProjectUrl>
     <PackageTags>rx mvvm async rx-main reactive</PackageTags>

diff --git a/Source/ReactiveProperty.NETStandard/Helpers/FilteredReadOnlyObservableCollection.cs b/Source/ReactiveProperty.NETStandard/Helpers/FilteredReadOnlyObservableCollection.cs
@@ -351,7 +351,16 @@ public void Dispose()
         CollectionChanged -= Source_CollectionChanged;
     }
 
-    private int FindNearIndex(int position) => IndexList.Take(position).Reverse().FirstOrDefault(x => x != null) ?? -1;
+    private int FindNearIndex(int position)
+    {
+        for (int i = position; i >= 0; i--)
+        {
+            var value = IndexList[i];
+            if (value != null) return value.Value;
+        }
+
+        return -1;
+    }
 
     private void AppearNewItem(int index)
     {