Merge branch 'master' into refactor/standardassetloader-public

src/Avalonia.Base/Data/Core/Plugins/DataAnnotationsValidationPlugin.cs

@@ -10,7 +10,7 @@ namespace Avalonia.Data.Core.Plugins
     /// <summary>
     /// Validates properties on that have <see cref="ValidationAttribute"/>s.
     /// </summary>
-    internal class DataAnnotationsValidationPlugin : IDataValidationPlugin
+    public class DataAnnotationsValidationPlugin : IDataValidationPlugin
     {
         /// <inheritdoc/>
         [RequiresUnreferencedCode(TrimmingMessages.DataValidationPluginRequiresUnreferencedCodeMessage)]

src/Avalonia.Base/Data/Core/Plugins/ExceptionValidationPlugin.cs

@@ -7,7 +7,7 @@ namespace Avalonia.Data.Core.Plugins
     /// <summary>
     /// Validates properties that report errors by throwing exceptions.
     /// </summary>
-    internal class ExceptionValidationPlugin : IDataValidationPlugin
+    public class ExceptionValidationPlugin : IDataValidationPlugin
     {
         /// <inheritdoc/>
         [RequiresUnreferencedCode(TrimmingMessages.DataValidationPluginRequiresUnreferencedCodeMessage)]

src/Avalonia.Base/Data/Core/Plugins/IndeiValidationPlugin.cs

@@ -10,7 +10,7 @@ namespace Avalonia.Data.Core.Plugins
     /// <summary>
     /// Validates properties on objects that implement <see cref="INotifyDataErrorInfo"/>.
     /// </summary>
-    internal class IndeiValidationPlugin : IDataValidationPlugin
+    public class IndeiValidationPlugin : IDataValidationPlugin
     {
         private static readonly WeakEvent<INotifyDataErrorInfo, DataErrorsChangedEventArgs>
             ErrorsChangedWeakEvent = WeakEvent.Register<INotifyDataErrorInfo, DataErrorsChangedEventArgs>(

src/Avalonia.Controls/Primitives/Thumb.cs

@@ -4,7 +4,6 @@ using Avalonia.Controls.Automation.Peers;
 using Avalonia.Controls.Metadata;
 using Avalonia.Input;
 using Avalonia.Interactivity;
-using Avalonia.VisualTree;
 
 namespace Avalonia.Controls.Primitives
 {
@@ -47,6 +46,12 @@ namespace Avalonia.Controls.Primitives
             remove { RemoveHandler(DragCompletedEvent, value); }
         }
 
+        internal void AdjustDrag(Vector v)
+        {
+            if (_lastPoint.HasValue)
+                _lastPoint = _lastPoint.Value + v;
+        }
+
         protected override AutomationPeer OnCreateAutomationPeer() => new ThumbAutomationPeer(this);
 
         protected virtual void OnDragStarted(VectorEventArgs e)
@@ -85,22 +90,20 @@ namespace Avalonia.Controls.Primitives
         {
             if (_lastPoint.HasValue)
             {
-                var point = e.GetPosition(null);
                 var ev = new VectorEventArgs
                 {
                     RoutedEvent = DragDeltaEvent,
-                    Vector = point - _lastPoint.Value,
+                    Vector = e.GetPosition(this) - _lastPoint.Value,
                 };
 
                 RaiseEvent(ev);
-                _lastPoint = point;
             }
         }
 
         protected override void OnPointerPressed(PointerPressedEventArgs e)
         {
             e.Handled = true;
-            _lastPoint = e.GetPosition(null);
+            _lastPoint = e.GetPosition(this);
 
             var ev = new VectorEventArgs
             {
@@ -123,7 +126,7 @@ namespace Avalonia.Controls.Primitives
                 var ev = new VectorEventArgs
                 {
                     RoutedEvent = DragCompletedEvent,
-                    Vector = (Vector)e.GetPosition(null),
+                    Vector = (Vector)e.GetPosition(this),
                 };
 
                 RaiseEvent(ev);

src/Avalonia.Controls/Primitives/Track.cs

@@ -45,6 +45,8 @@ namespace Avalonia.Controls.Primitives
         public static readonly StyledProperty<bool> IgnoreThumbDragProperty =
             AvaloniaProperty.Register<Track, bool>(nameof(IgnoreThumbDrag));
 
+        private Vector _lastDrag;
+
         static Track()
         {
             ThumbProperty.Changed.AddClassHandler<Track>((x, e) => x.ThumbChanged(e));
@@ -245,7 +247,10 @@ namespace Avalonia.Controls.Primitives
 
                 if (Thumb != null)
                 {
-                    Thumb.Arrange(new Rect(offset, pieceSize));
+                    var bounds = new Rect(offset, pieceSize);
+                    var adjust = CalculateThumbAdjustment(Thumb, bounds);
+                    Thumb.Arrange(bounds);
+                    Thumb.AdjustDrag(adjust);
                 }
 
                 ThumbCenterOffset = offset.Y + (thumbLength * 0.5);
@@ -277,12 +282,16 @@ namespace Avalonia.Controls.Primitives
 
                 if (Thumb != null)
                 {
-                    Thumb.Arrange(new Rect(offset, pieceSize));
+                    var bounds = new Rect(offset, pieceSize);
+                    var adjust = CalculateThumbAdjustment(Thumb, bounds);
+                    Thumb.Arrange(bounds);
+                    Thumb.AdjustDrag(adjust);
                 }
 
                 ThumbCenterOffset = offset.X + (thumbLength * 0.5);
             }
 
+            _lastDrag = default;
             return arrangeSize;
         }
 
@@ -296,6 +305,12 @@ namespace Avalonia.Controls.Primitives
             }
         }
 
+        private Vector CalculateThumbAdjustment(Thumb thumb, Rect newThumbBounds)
+        {
+            var thumbDelta = newThumbBounds.Position - thumb.Bounds.Position;
+            return _lastDrag - thumbDelta;
+        }
+
         private static void CoerceLength(ref double componentLength, double trackLength)
         {
             if (componentLength < 0)
@@ -440,10 +455,17 @@ namespace Avalonia.Controls.Primitives
             if (IgnoreThumbDrag)
                 return;
 
+            var value = Value;
+            var delta = ValueFromDistance(e.Vector.X, e.Vector.Y);
+            var factor = e.Vector / delta;
+
             SetCurrentValue(ValueProperty, MathUtilities.Clamp(
-                Value + ValueFromDistance(e.Vector.X, e.Vector.Y),
+                value + delta,
                 Minimum,
                 Maximum));
+            
+            // Record the part of the drag that actually had effect as the last drag delta.
+            _lastDrag = (Value - value) * factor;
         }
 
         private void ShowChildren(bool visible)

src/Avalonia.Controls/TreeViewItem.cs

@@ -165,7 +165,7 @@ namespace Avalonia.Controls
                     {
                         Key.Left => ApplyToItemOrRecursivelyIfCtrl(FocusAwareCollapseItem, e.KeyModifiers),
                         Key.Right => ApplyToItemOrRecursivelyIfCtrl(ExpandItem, e.KeyModifiers),
-                        Key.Enter or Key.Space => ApplyToItemOrRecursivelyIfCtrl(IsExpanded ? CollapseItem : ExpandItem, e.KeyModifiers),
+                        Key.Enter => ApplyToItemOrRecursivelyIfCtrl(IsExpanded ? CollapseItem : ExpandItem, e.KeyModifiers),
 
                         // do not handle CTRL with numpad keys
                         Key.Subtract => FocusAwareCollapseItem,

src/Avalonia.Native/AvaloniaNativeDragSource.cs

@@ -4,7 +4,6 @@ using System.Threading.Tasks;
 using Avalonia.Controls;
 using Avalonia.Input;
 using Avalonia.Input.Platform;
-using Avalonia.Interactivity;
 using Avalonia.Native.Interop;
 
 namespace Avalonia.Native
@@ -18,16 +17,6 @@ namespace Avalonia.Native
             _factory = factory;
         }
 
-        private static TopLevel FindRoot(object? element)
-        {
-            while (element is Interactive interactive && element is not Visual)
-                element = interactive.GetInteractiveParent();
-            if (element == null)
-                return null;
-            var visual = (Visual)element;
-            return TopLevel.GetTopLevel(visual);
-        }
-
         class DndCallback : NativeCallbackBase, IAvnDndResultCallback
         {
             private TaskCompletionSource<DragDropEffects> _tcs;
@@ -46,7 +35,7 @@ namespace Avalonia.Native
         public Task<DragDropEffects> DoDragDrop(PointerEventArgs triggerEvent, IDataObject data, DragDropEffects allowedEffects)
         {
             // Sanity check
-            var tl = FindRoot(triggerEvent.Source);
+            var tl = TopLevel.GetTopLevel(triggerEvent.Source as Visual);
             var view = tl?.PlatformImpl as WindowBaseImpl;
             if (view == null)
                 throw new ArgumentException();

src/Windows/Avalonia.Win32/Win32StorageProvider.cs

@@ -99,12 +99,14 @@ namespace Avalonia.Win32
                     }
                     frm.SetOptions(options);
 
-                    if (defaultExtension is not null)
+                    if (defaultExtension is null)
                     {
-                        fixed (char* pExt = defaultExtension)
-                        {
-                            frm.SetDefaultExtension(pExt);
-                        }
+                        defaultExtension = String.Empty;
+                    }
+
+                    fixed (char* pExt = defaultExtension)
+                    {
+                        frm.SetDefaultExtension(pExt);
                     }
 
                     suggestedFileName ??= "";

tests/Avalonia.Controls.UnitTests/ScrollViewerTests.cs

@@ -1,10 +1,13 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using Avalonia.Controls.Presenters;
 using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Templates;
 using Avalonia.Layout;
+using Avalonia.Media;
 using Avalonia.UnitTests;
+using Avalonia.VisualTree;
 using Moq;
 using Xunit;
 
@@ -12,6 +15,8 @@ namespace Avalonia.Controls.UnitTests
 {
     public class ScrollViewerTests
     {
+        private readonly MouseTestHelper _mouse = new();
+
         [Fact]
         public void Content_Is_Created()
         {
@@ -249,6 +254,121 @@ namespace Avalonia.Controls.UnitTests
             Assert.Equal(new Vector(20, 20), target.Offset); 
         }
 
+        [Fact]
+        public void Scroll_Does_Not_Jump_When_Viewport_Becomes_Smaller_While_Dragging_ScrollBar_Thumb()
+        {
+            var content = new TestContent
+            {
+                MeasureSize = new Size(1000, 10000),
+            };
+
+            var target = new ScrollViewer
+            {
+                Template = new FuncControlTemplate<ScrollViewer>(CreateTemplate),
+                Content = content,
+            };
+            var root = new TestRoot(target);
+
+            root.LayoutManager.ExecuteInitialLayoutPass();
+
+            Assert.Equal(new Size(1000, 10000), target.Extent);
+            Assert.Equal(new Size(1000, 1000), target.Viewport);
+
+            // We're working in absolute coordinates (i.e. relative to the root) and clicking on
+            // the center of the vertical thumb.
+            var thumb = GetVerticalThumb(target);
+            var p = GetRootPoint(thumb, thumb.Bounds.Center);
+
+            // Press the mouse button in the center of the thumb.
+            _mouse.Down(thumb, position: p);
+            root.LayoutManager.ExecuteLayoutPass();
+
+            // Drag the thumb down 300 pixels.
+            _mouse.Move(thumb, p += new Vector(0, 300));
+            root.LayoutManager.ExecuteLayoutPass();
+
+            Assert.Equal(new Vector(0, 3000), target.Offset);
+            Assert.Equal(300, thumb.Bounds.Top);
+
+            // Now the extent changes from 10,000 to 5000.
+            content.MeasureSize /= 2;
+            content.InvalidateMeasure();
+            root.LayoutManager.ExecuteLayoutPass();
+
+            // Due to the extent change, the thumb moves down but the value remains the same.
+            Assert.Equal(600, thumb.Bounds.Top);
+            Assert.Equal(new Vector(0, 3000), target.Offset);
+
+            // Drag the thumb down another 100 pixels.
+            _mouse.Move(thumb, p += new Vector(0, 100));
+            root.LayoutManager.ExecuteLayoutPass();
+
+            // The drag should not cause the offset/thumb to jump *up* to the current absolute
+            // mouse position, i.e. it should move down in the direction of the drag even if the
+            // absolute mouse position is now above the thumb.
+            Assert.Equal(700, thumb.Bounds.Top);
+            Assert.Equal(new Vector(0, 3500), target.Offset);
+        }
+
+        [Fact]
+        public void Thumb_Does_Not_Become_Detached_From_Mouse_Position_When_Scrolling_Past_The_Start()
+        {
+            var content = new TestContent();
+            var target = new ScrollViewer
+            {
+                Template = new FuncControlTemplate<ScrollViewer>(CreateTemplate),
+                Content = content,
+            };
+            var root = new TestRoot(target);
+
+            root.LayoutManager.ExecuteInitialLayoutPass();
+
+            Assert.Equal(new Size(1000, 2000), target.Extent);
+            Assert.Equal(new Size(1000, 1000), target.Viewport);
+
+            // We're working in absolute coordinates (i.e. relative to the root) and clicking on
+            // the center of the vertical thumb.
+            var thumb = GetVerticalThumb(target);
+            var p = GetRootPoint(thumb, thumb.Bounds.Center);
+
+            // Press the mouse button in the center of the thumb.
+            _mouse.Down(thumb, position: p);
+            root.LayoutManager.ExecuteLayoutPass();
+
+            // Drag the thumb down 100 pixels.
+            _mouse.Move(thumb, p += new Vector(0, 100));
+            root.LayoutManager.ExecuteLayoutPass();
+
+            Assert.Equal(new Vector(0, 200), target.Offset);
+            Assert.Equal(100, thumb.Bounds.Top);
+
+            // Drag the thumb up 200 pixels - 100 pixels past the top of the scrollbar.
+            _mouse.Move(thumb, p -= new Vector(0, 200));
+            root.LayoutManager.ExecuteLayoutPass();
+
+            Assert.Equal(new Vector(0, 0), target.Offset);
+            Assert.Equal(0, thumb.Bounds.Top);
+
+            // Drag the thumb back down 200 pixels.
+            _mouse.Move(thumb, p += new Vector(0, 200));
+            root.LayoutManager.ExecuteLayoutPass();
+
+            // We should now be back in the state after we first scrolled down 100 pixels.
+            Assert.Equal(new Vector(0, 200), target.Offset);
+            Assert.Equal(100, thumb.Bounds.Top);
+        }
+
+        private Point GetRootPoint(Visual control, Point p)
+        {
+            if (control.GetVisualRoot() is Visual root &&
+                control.TransformToVisual(root) is Matrix m)
+            {
+                return p.Transform(m);
+            }
+
+            throw new InvalidOperationException("Could not get the point in root coordinates.");
+        }
+
         private Control CreateTemplate(ScrollViewer control, INameScope scope)
         {
             return new Grid
@@ -273,6 +393,7 @@ namespace Avalonia.Controls.UnitTests
                     {
                         Name = "PART_HorizontalScrollBar",
                         Orientation = Orientation.Horizontal,
+                        Template = new FuncControlTemplate<ScrollBar>(CreateScrollBarTemplate),
                         [~ScrollBar.VisibilityProperty] = control[~ScrollViewer.HorizontalScrollBarVisibilityProperty],
                         [Grid.RowProperty] = 1,
                     }.RegisterInNameScope(scope),
@@ -280,6 +401,7 @@ namespace Avalonia.Controls.UnitTests
                     {
                         Name = "PART_VerticalScrollBar",
                         Orientation = Orientation.Vertical,
+                        Template = new FuncControlTemplate<ScrollBar>(CreateScrollBarTemplate),
                         [~ScrollBar.VisibilityProperty] = control[~ScrollViewer.VerticalScrollBarVisibilityProperty],
                         [Grid.ColumnProperty] = 1,
                     }.RegisterInNameScope(scope),
@@ -287,6 +409,44 @@ namespace Avalonia.Controls.UnitTests
             };
         }
 
+        private Control CreateScrollBarTemplate(ScrollBar scrollBar, INameScope scope)
+        {
+            return new Border
+            {
+                Child = new Track
+                {
+                    Name = "track",
+                    IsDirectionReversed = true,
+                    [!Track.MinimumProperty] = scrollBar[!RangeBase.MinimumProperty],
+                    [!Track.MaximumProperty] = scrollBar[!RangeBase.MaximumProperty],
+                    [!!Track.ValueProperty] = scrollBar[!!RangeBase.ValueProperty],
+                    [!Track.ViewportSizeProperty] = scrollBar[!ScrollBar.ViewportSizeProperty],
+                    [!Track.OrientationProperty] = scrollBar[!ScrollBar.OrientationProperty],
+                    Thumb = new Thumb
+                    {
+                        Template = new FuncControlTemplate<Thumb>(CreateThumbTemplate),
+                    },
+                }.RegisterInNameScope(scope),
+            };
+        }
+
+        private static Control CreateThumbTemplate(Thumb control, INameScope scope)
+        {
+            return new Border
+            {
+                Background = Brushes.Gray,
+            };
+        }
+
+        private Thumb GetVerticalThumb(ScrollViewer target)
+        {
+            var scrollbar = Assert.IsType<ScrollBar>(
+                target.GetTemplateChildren().FirstOrDefault(x => x.Name == "PART_VerticalScrollBar"));
+            var track = Assert.IsType<Track>(
+                scrollbar.GetTemplateChildren().FirstOrDefault(x => x.Name == "track"));
+            return Assert.IsType<Thumb>(track.Thumb);
+        }
+
         private static void InitializeScrollViewer(ScrollViewer target)
         {
             target.ApplyTemplate();
@@ -295,5 +455,15 @@ namespace Avalonia.Controls.UnitTests
             presenter.AttachToScrollViewer();
             presenter.UpdateChild();
         }
+
+        private class TestContent : Control
+        {
+            public Size MeasureSize { get; set; } = new Size(1000, 2000);
+
+            protected override Size MeasureOverride(Size availableSize)
+            {
+                return MeasureSize;
+            }
+        }
     }
 }

tests/Avalonia.UnitTests/MouseTestHelper.cs

@@ -59,7 +59,7 @@ namespace Avalonia.UnitTests
             {
                 _pressedButton = mouseButton;
                 _pointer.Capture((IInputElement)target);
-                source.RaiseEvent(new PointerPressedEventArgs(source, _pointer, (Visual)source, position, Timestamp(), props,
+                source.RaiseEvent(new PointerPressedEventArgs(source, _pointer, GetRoot(target), position, Timestamp(), props,
                     modifiers, clickCount));
             }
         }
@@ -68,7 +68,7 @@ namespace Avalonia.UnitTests
 
         public void Move(Interactive target, Interactive source, in Point position, KeyModifiers modifiers = default)
         {
-            target.RaiseEvent(new PointerEventArgs(InputElement.PointerMovedEvent, source, _pointer, (Visual)target, position,
+            target.RaiseEvent(new PointerEventArgs(InputElement.PointerMovedEvent, source, _pointer, GetRoot(target), position,
                 Timestamp(), new PointerPointProperties((RawInputModifiers)_pressedButtons, PointerUpdateKind.Other), modifiers));
         }
 
@@ -88,7 +88,7 @@ namespace Avalonia.UnitTests
             );
             if (ButtonCount(props) == 0)
             {
-                target.RaiseEvent(new PointerReleasedEventArgs(source, _pointer, (Visual)target, position,
+                target.RaiseEvent(new PointerReleasedEventArgs(source, _pointer, GetRoot(target), position,
                     Timestamp(), props, modifiers, _pressedButton));
                 _pointer.Capture(null);
             }
@@ -131,5 +131,9 @@ namespace Avalonia.UnitTests
                 Timestamp(), new PointerPointProperties((RawInputModifiers)_pressedButtons, PointerUpdateKind.Other), KeyModifiers.None));
         }
 
+        private Visual GetRoot(Interactive source)
+        {
+            return ((source as Visual)?.GetVisualRoot() as Visual) ?? (Visual)source;
+        }
     }
 }