Merge branch 'feature/selectionmodel' into feature/selectionmodel-changed-notifications

src/Avalonia.Controls/SelectionModel.cs

@@ -529,7 +529,7 @@ namespace Avalonia.Controls
             OnSelectionChanged(e);
         }
 
-        internal object? ResolvePath(object data, SelectionNode sourceNode)
+        internal object? ResolvePath(object data, IndexPath dataIndexPath)
         {
             object? resolved = null;
 
@@ -538,18 +538,18 @@ namespace Avalonia.Controls
             {
                 if (_childrenRequestedEventArgs == null)
                 {
-                    _childrenRequestedEventArgs = new SelectionModelChildrenRequestedEventArgs(data, sourceNode);
+                    _childrenRequestedEventArgs = new SelectionModelChildrenRequestedEventArgs(data, dataIndexPath, false);
                 }
                 else
                 {
-                    _childrenRequestedEventArgs.Initialize(data, sourceNode);
+                    _childrenRequestedEventArgs.Initialize(data, dataIndexPath, false);
                 }
 
                 ChildrenRequested(this, _childrenRequestedEventArgs);
                 resolved = _childrenRequestedEventArgs.Children;
 
                 // Clear out the values in the args so that it cannot be used after the event handler call.
-                _childrenRequestedEventArgs.Initialize(null, null);
+                _childrenRequestedEventArgs.Initialize(null, default, true);
             }
             else
             {

src/Avalonia.Controls/SelectionModelChildrenRequestedEventArgs.cs

@@ -12,12 +12,16 @@ namespace Avalonia.Controls
     public class SelectionModelChildrenRequestedEventArgs : EventArgs
     {
         private object? _source;
-        private SelectionNode? _sourceNode;
-
-        internal SelectionModelChildrenRequestedEventArgs(object source, SelectionNode sourceNode)
+        private IndexPath _sourceIndexPath;
+        private bool _throwOnAccess;
+        
+        internal SelectionModelChildrenRequestedEventArgs(
+            object source,
+            IndexPath sourceIndexPath,
+            bool throwOnAccess)
         {
-            _source = source;
-            _sourceNode = sourceNode;
+            source = source ?? throw new ArgumentNullException(nameof(source));
+            Initialize(source, sourceIndexPath, throwOnAccess);
         }
 
         public object? Children { get; set; }
@@ -26,12 +30,12 @@ namespace Avalonia.Controls
         {
             get
             {
-                if (_source == null)
+                if (_throwOnAccess)
                 {
                     throw new ObjectDisposedException(nameof(SelectionModelChildrenRequestedEventArgs));
                 }
 
-                return _source;
+                return _source!;
             }
         }
 
@@ -39,19 +43,28 @@ namespace Avalonia.Controls
         {
             get
             {
-                if (_sourceNode == null)
+                if (_throwOnAccess)
                 {
                     throw new ObjectDisposedException(nameof(SelectionModelChildrenRequestedEventArgs));
                 }
 
-                return _sourceNode.IndexPath;
+                return _sourceIndexPath;
             }
         }
 
-        internal void Initialize(object? source, SelectionNode? sourceNode)
+        internal void Initialize(
+            object? source,
+            IndexPath sourceIndexPath,
+            bool throwOnAccess)
         {
+            if (!throwOnAccess && source == null)
+            {
+                throw new ArgumentNullException(nameof(source));
+            }
+
             _source = source;
-            _sourceNode = sourceNode;
+            _sourceIndexPath = sourceIndexPath;
+            _throwOnAccess = throwOnAccess;
         }
     }
 }

src/Avalonia.Controls/SelectionNode.cs

@@ -133,7 +133,8 @@ namespace Avalonia.Controls
                     
                     if (childData != null)
                     {
-                        var resolvedChild = _manager.ResolvePath(childData, this);
+                        var childDataIndexPath = IndexPath.CloneWithChildIndex(index);
+                        var resolvedChild = _manager.ResolvePath(childData, childDataIndexPath);
                         
                         if (resolvedChild != null)
                         {

tests/Avalonia.Controls.UnitTests/SelectionModelTests.cs

@@ -277,21 +277,21 @@ namespace Avalonia.Controls.UnitTests
                 // Validate SourceIndices.
                 var expectedSourceIndices = new List<IndexPath>()
                 {
-                    Path(),
                     Path(1),
                     Path(1, 0),
-                    Path(1),
-                    Path(1, 0, 1),
-                    Path(1, 0, 1),
-                    Path(1, 0, 1),
                     Path(1, 0, 1),
                     Path(1, 1),
-                    Path(1, 1),
-                    Path(1, 1, 0),
-                    Path(1, 1, 0),
-                    Path(1, 1, 0),
+                    Path(1, 0, 1, 3),
+                    Path(1, 0, 1, 2),
+                    Path(1, 0, 1, 1),
+                    Path(1, 0, 1, 0),
+                    Path(1, 1, 1),
                     Path(1, 1, 0),
-                    Path(1, 1, 1)
+                    Path(1, 1, 0, 3),
+                    Path(1, 1, 0, 2),
+                    Path(1, 1, 0, 1),
+                    Path(1, 1, 0, 0),
+                    Path(1, 1, 1, 0)
                 };
 
                 Assert.Equal(expectedSourceIndices.Count, sourcePaths.Count);