From cdb4e9051854d2d7eff66993ae2733de28cec315 Mon Sep 17 00:00:00 2001
From: Yoh Deadfall <yoh.deadfall@hotmail.com>
Date: Thu, 15 Oct 2020 19:37:28 +0300
Subject: [PATCH 1/2] Simplified conditions

---
 .../Primitives/SelectingItemsControl.cs       | 20 +++++++------------
 1 file changed, 7 insertions(+), 13 deletions(-)

diff --git a/src/Avalonia.Controls/Primitives/SelectingItemsControl.cs b/src/Avalonia.Controls/Primitives/SelectingItemsControl.cs
index e34b3b145f..4786e88fca 100644
--- a/src/Avalonia.Controls/Primitives/SelectingItemsControl.cs
+++ b/src/Avalonia.Controls/Primitives/SelectingItemsControl.cs
@@ -794,18 +794,13 @@ namespace Avalonia.Controls.Primitives
         /// <param name="e">The event.</param>
         private void ContainerSelectionChanged(RoutedEventArgs e)
         {
-            if (!_ignoreContainerSelectionChanged)
+            if (!_ignoreContainerSelectionChanged &&
+                e.Source is IControl control &&
+                e.Source is ISelectable selectable &&
+                control.LogicalParent == this &&
+                ItemContainerGenerator?.IndexFromContainer(control) != -1)
             {
-                var control = e.Source as IControl;
-                var selectable = e.Source as ISelectable;
-
-                if (control != null &&
-                    selectable != null &&
-                    control.LogicalParent == this &&
-                    ItemContainerGenerator?.IndexFromContainer(control) != -1)
-                {
-                    UpdateSelection(control, selectable.IsSelected);
-                }
+                UpdateSelection(control, selectable.IsSelected);
             }
 
             if (e.Source != this)
@@ -824,12 +819,11 @@ namespace Avalonia.Controls.Primitives
         {
             try
             {
-                var selectable = container as ISelectable;
                 bool result;
 
                 _ignoreContainerSelectionChanged = true;
 
-                if (selectable != null)
+                if (container is ISelectable selectable)
                 {
                     result = selectable.IsSelected;
                     selectable.IsSelected = selected;

From 3b48238fe07642d780740a9b1c26a0b6860374ff Mon Sep 17 00:00:00 2001
From: Yoh Deadfall <yoh.deadfall@hotmail.com>
Date: Thu, 15 Oct 2020 19:38:06 +0300
Subject: [PATCH 2/2] Removed dead code

---
 .../Primitives/SelectingItemsControl.cs           | 15 ---------------
 1 file changed, 15 deletions(-)

diff --git a/src/Avalonia.Controls/Primitives/SelectingItemsControl.cs b/src/Avalonia.Controls/Primitives/SelectingItemsControl.cs
index 4786e88fca..301487ebb6 100644
--- a/src/Avalonia.Controls/Primitives/SelectingItemsControl.cs
+++ b/src/Avalonia.Controls/Primitives/SelectingItemsControl.cs
@@ -842,21 +842,6 @@ namespace Avalonia.Controls.Primitives
             }
         }
 
-        /// <summary>
-        /// Sets an item container's 'selected' class or <see cref="ISelectable.IsSelected"/>.
-        /// </summary>
-        /// <param name="index">The index of the item.</param>
-        /// <param name="selected">Whether the item should be selected or deselected.</param>
-        private void MarkItemSelected(int index, bool selected)
-        {
-            var container = ItemContainerGenerator?.ContainerFromIndex(index);
-
-            if (container != null)
-            {
-                MarkContainerSelected(container, selected);
-            }
-        }
-
         private void UpdateContainerSelection()
         {
             if (Presenter?.Panel is IPanel panel)