Merge branch 'master' into fix-nested-popups

src/Avalonia.Controls/Primitives/SelectingItemsControl.cs

@@ -304,6 +304,11 @@ namespace Avalonia.Controls.Primitives
         {
             base.ItemsCollectionChanged(sender, e);
 
+            if (_updateCount > 0)
+            {
+                return;
+            }
+
             switch (e.Action)
             {
                 case NotifyCollectionChangedAction.Add:
@@ -1071,13 +1076,20 @@ namespace Avalonia.Controls.Primitives
 
         private void UpdateFinished()
         {
-            if (_updateSelectedIndex != int.MinValue)
+            if (_updateSelectedItem != null)
             {
-                SelectedIndex = _updateSelectedIndex;
+                SelectedItem = _updateSelectedItem;
             }
-            else if (_updateSelectedItem != null)
+            else
             {
-                SelectedItem = _updateSelectedItem;
+                if (ItemCount == 0 && SelectedIndex != -1)
+                {
+                    SelectedIndex = -1;
+                }
+                else
+                {
+                    SelectedIndex = _updateSelectedIndex != int.MinValue ? _updateSelectedIndex : 0;
+                }
             }
         }
 

src/Avalonia.Styling/Controls/ResourceProviderExtensions.cs → src/Avalonia.Styling/Controls/ResourceNodeExtensions.cs

@@ -3,7 +3,7 @@ using Avalonia.Reactive;
 
 namespace Avalonia.Controls
 {
-    public static class ResourceProviderExtensions
+    public static class ResourceNodeExtensions
     {
         /// <summary>
         /// Finds the specified resource by searching up the logical tree and then global styles.

src/Markup/Avalonia.Markup.Xaml/MarkupExtensions/DynamicResourceExtension.cs

@@ -18,7 +18,7 @@ namespace Avalonia.Markup.Xaml.MarkupExtensions
         {
         }
 
-        public DynamicResourceExtension(string resourceKey)
+        public DynamicResourceExtension(object resourceKey)
         {
             ResourceKey = resourceKey;
         }

src/Markup/Avalonia.Markup.Xaml/MarkupExtensions/StaticResourceExtension.cs

@@ -16,12 +16,12 @@ namespace Avalonia.Markup.Xaml.MarkupExtensions
         {
         }
 
-        public StaticResourceExtension(string resourceKey)
+        public StaticResourceExtension(object resourceKey)
         {
             ResourceKey = resourceKey;
         }
 
-        public string ResourceKey { get; set; }
+        public object ResourceKey { get; set; }
 
         public object ProvideValue(IServiceProvider serviceProvider)
         {

tests/Avalonia.Controls.UnitTests/Primitives/SelectingItemsControlTests.cs

@@ -109,6 +109,28 @@ namespace Avalonia.Controls.UnitTests.Primitives
             Assert.True(items[1].IsSelected);
         }
 
+        [Fact]
+        public void Setting_SelectedIndex_During_Initialize_Should_Select_Item_When_AlwaysSelected_Is_Used()
+        {
+            var listBox = new ListBox
+            {
+                SelectionMode = SelectionMode.Single | SelectionMode.AlwaysSelected
+            };
+
+            listBox.BeginInit();
+
+            listBox.SelectedIndex = 1;
+            var items = new AvaloniaList<string>();
+            listBox.Items = items;
+            items.Add("A");
+            items.Add("B");
+            items.Add("C");
+
+            listBox.EndInit();
+
+            Assert.Equal("B", listBox.SelectedItem);
+        }
+
         [Fact]
         public void Setting_SelectedIndex_Before_ApplyTemplate_Should_Set_Item_IsSelected_True()
         {