Merge branch 'master' into sdoroff-shape-layout-fixed

.travis.yml

@@ -8,7 +8,7 @@ env:
     - DOTNET_SKIP_FIRST_TIME_EXPERIENCE=1
     - DOTNET_CLI_TELEMETRY_OPTOUT=1
 mono:
-  - latest
+  - 5.2.0
 dotnet: 2.0.0
 script:
   - ./build.sh --target "Travis" --platform "Mono" --configuration "Release"

samples/ControlCatalog/SideBar.xaml

@@ -1,11 +1,11 @@
-<Styles xmlns="https://github.com/avaloniaui">
+<Styles xmlns="https://github.com/avaloniaui" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <Style Selector="TabControl.sidebar">
     <Setter Property="Template">
       <ControlTemplate>
         <DockPanel>
           <ScrollViewer MinWidth="190" Background="{DynamicResource ThemeAccentBrush}" DockPanel.Dock="Left">
             <TabStrip Name="PART_TabStrip"
-                      MemberSelector="{Static TabControl.HeaderSelector}"
+                      MemberSelector="{x:Static TabControl.HeaderSelector}"
                       Items="{TemplateBinding Items}"
                       SelectedIndex="{TemplateBinding Path=SelectedIndex, Mode=TwoWay}">
               <TabStrip.ItemsPanel>
@@ -17,7 +17,7 @@
           </ScrollViewer>
           <Carousel Name="PART_Content"
                     Margin="8 0 0 0"
-                    MemberSelector="{Static TabControl.ContentSelector}"
+                    MemberSelector="{x:Static TabControl.ContentSelector}"
                     Items="{TemplateBinding Items}"
                     SelectedIndex="{TemplateBinding Path=SelectedIndex}"
                     Transition="{TemplateBinding Transition}"

samples/RenderTest/SideBar.xaml

@@ -1,11 +1,11 @@
-<Styles xmlns="https://github.com/avaloniaui">
+<Styles xmlns="https://github.com/avaloniaui" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <Style Selector="TabControl.sidebar">
     <Setter Property="Template">
       <ControlTemplate>
         <DockPanel>
           <ScrollViewer MinWidth="190" Background="{DynamicResource ThemeAccentBrush}" DockPanel.Dock="Left">
             <TabStrip Name="PART_TabStrip"
-                      MemberSelector="{Static TabControl.HeaderSelector}"
+                      MemberSelector="{x:Static TabControl.HeaderSelector}"
                       Items="{TemplateBinding Items}"
                       SelectedIndex="{TemplateBinding Path=SelectedIndex, Mode=TwoWay}">
               <TabStrip.ItemsPanel>
@@ -17,7 +17,7 @@
           </ScrollViewer>
           <Carousel Name="PART_Content"
                     Margin="8 0 0 0"
-                    MemberSelector="{Static TabControl.ContentSelector}"
+                    MemberSelector="{x:Static TabControl.ContentSelector}"
                     Items="{TemplateBinding Items}"
                     SelectedIndex="{TemplateBinding Path=SelectedIndex}"
                     Transition="{TemplateBinding Transition}"

samples/VirtualizationTest/ViewModels/MainWindowViewModel.cs

@@ -17,7 +17,7 @@ namespace VirtualizationTest.ViewModels
         private int _newItemIndex;
         private IReactiveList<ItemViewModel> _items;
         private string _prefix = "Item";
-        private Orientation _orientation;
+        private Orientation _orientation = Orientation.Vertical;
         private ItemVirtualizationMode _virtualizationMode = ItemVirtualizationMode.Simple;
 
         public MainWindowViewModel()

src/Avalonia.Controls/Control.cs

@@ -101,6 +101,7 @@ namespace Avalonia.Controls
         private Styles _styles;
         private bool _styled;
         private Subject<IStyleable> _styleDetach = new Subject<IStyleable>();
+        private bool _dataContextUpdating;
 
         /// <summary>
         /// Initializes static members of the <see cref="Control"/> class.
@@ -111,6 +112,7 @@ namespace Avalonia.Controls
             PseudoClass(IsEnabledCoreProperty, x => !x, ":disabled");
             PseudoClass(IsFocusedProperty, ":focus");
             PseudoClass(IsPointerOverProperty, ":pointerover");
+            DataContextProperty.Changed.AddClassHandler<Control>(x => x.OnDataContextChangedCore);
         }
 
         /// <summary>
@@ -681,18 +683,26 @@ namespace Avalonia.Controls
         }
 
         /// <summary>
-        /// Called before the <see cref="DataContext"/> property changes.
+        /// Called when the <see cref="DataContext"/> property changes.
         /// </summary>
-        protected virtual void OnDataContextChanging()
+        /// <param name="e">The event args.</param>
+        protected virtual void OnDataContextChanged(EventArgs e)
         {
+            DataContextChanged?.Invoke(this, EventArgs.Empty);
         }
 
         /// <summary>
-        /// Called after the <see cref="DataContext"/> property changes.
+        /// Called when the <see cref="DataContext"/> begins updating.
         /// </summary>
-        protected virtual void OnDataContextChanged()
+        protected virtual void OnDataContextBeginUpdate()
+        {
+        }
+
+        /// <summary>
+        /// Called when the <see cref="DataContext"/> finishes updating.
+        /// </summary>
+        protected virtual void OnDataContextEndUpdate()
         {
-            DataContextChanged?.Invoke(this, EventArgs.Empty);
         }
 
         /// <inheritdoc/>
@@ -745,24 +755,38 @@ namespace Avalonia.Controls
             }
         }
 
-        /// <summary>
-        /// Called when the <see cref="DataContext"/> property begins and ends being notified.
-        /// </summary>
-        /// <param name="o">The object on which the DataContext is changing.</param>
-        /// <param name="notifying">Whether the notifcation is beginning or ending.</param>
         private static void DataContextNotifying(IAvaloniaObject o, bool notifying)
         {
-            var control = o as Control;
+            if (o is Control control)
+            {
+                DataContextNotifying(control, notifying);
+            }
+        }
 
-            if (control != null)
+        private static void DataContextNotifying(Control control, bool notifying)
+        {
+            if (notifying)
             {
-                if (notifying)
+                if (!control._dataContextUpdating)
                 {
-                    control.OnDataContextChanging();
+                    control._dataContextUpdating = true;
+                    control.OnDataContextBeginUpdate();
+
+                    foreach (var child in control.LogicalChildren)
+                    {
+                        if (child is Control c && !c.IsSet(DataContextProperty))
+                        {
+                            DataContextNotifying(c, notifying);
+                        }
+                    }
                 }
-                else
+            }
+            else
+            {
+                if (control._dataContextUpdating)
                 {
-                    control.OnDataContextChanged();
+                    control.OnDataContextEndUpdate();
+                    control._dataContextUpdating = false;
                 }
             }
         }
@@ -881,6 +905,11 @@ namespace Avalonia.Controls
             }
         }
 
+        private void OnDataContextChangedCore(AvaloniaPropertyChangedEventArgs e)
+        {
+            OnDataContextChanged(EventArgs.Empty);
+        }
+
         private void LogicalChildrenCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
         {
             switch (e.Action)

src/Avalonia.Controls/Primitives/SelectingItemsControl.cs

@@ -414,16 +414,16 @@ namespace Avalonia.Controls.Primitives
         }
 
         /// <inheritdoc/>
-        protected override void OnDataContextChanging()
+        protected override void OnDataContextBeginUpdate()
         {
-            base.OnDataContextChanging();
+            base.OnDataContextBeginUpdate();
             ++_updateCount;
         }
 
         /// <inheritdoc/>
-        protected override void OnDataContextChanged()
+        protected override void OnDataContextEndUpdate()
         {
-            base.OnDataContextChanged();
+            base.OnDataContextEndUpdate();
 
             if (--_updateCount == 0)
             {

src/Avalonia.Styling/LogicalTree/LogicalExtensions.cs

@@ -50,6 +50,16 @@ namespace Avalonia.LogicalTree
             }
         }
 
+        public static IEnumerable<ILogical> GetSelfAndLogicalDescendants(this ILogical logical)
+        {
+            yield return logical;
+
+            foreach (var descendent in logical.GetLogicalDescendants())
+            {
+                yield return descendent;
+            }
+        }
+
         public static ILogical GetLogicalParent(this ILogical logical)
         {
             return logical.LogicalParent;

src/Avalonia.Styling/Styling/Setter.cs

@@ -141,20 +141,20 @@ namespace Avalonia.Styling
             {
                 var description = style?.ToString();
 
-                if (sourceInstance.Subject != null)
+                if (sourceInstance.Mode == BindingMode.TwoWay || sourceInstance.Mode == BindingMode.OneWayToSource)
                 {
                     var activated = new ActivatedSubject(activator, sourceInstance.Subject, description);
                     cloned = new InstancedBinding(activated, sourceInstance.Mode, BindingPriority.StyleTrigger);
                 }
-                else if (sourceInstance.Observable != null)
+                else if (sourceInstance.Mode == BindingMode.OneTime)
                 {
-                    var activated = new ActivatedObservable(activator, sourceInstance.Observable, description);
-                    cloned = new InstancedBinding(activated, sourceInstance.Mode, BindingPriority.StyleTrigger);
+                    var activated = new ActivatedValue(activator, sourceInstance.Value, description);
+                    cloned = new InstancedBinding(activated, BindingMode.OneWay, BindingPriority.StyleTrigger);
                 }
                 else
                 {
-                    var activated = new ActivatedValue(activator, sourceInstance.Value, description);
-                    cloned = new InstancedBinding(activated, BindingMode.OneWay, BindingPriority.StyleTrigger);
+                    var activated = new ActivatedObservable(activator, sourceInstance.Observable ?? sourceInstance.Subject, description);
+                    cloned = new InstancedBinding(activated, sourceInstance.Mode, BindingPriority.StyleTrigger);
                 }
             }
             else

src/Avalonia.Themes.Default/TabControl.xaml

@@ -1,4 +1,4 @@
-<Styles xmlns="https://github.com/avaloniaui">
+<Styles xmlns="https://github.com/avaloniaui"  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <Style Selector="TabControl">
     <Setter Property="Template">
       <ControlTemplate>
@@ -7,11 +7,11 @@
                 BorderThickness="{TemplateBinding BorderThickness}">
           <DockPanel>
             <TabStrip Name="PART_TabStrip"
-                      MemberSelector="{Static TabControl.HeaderSelector}"
+                      MemberSelector="{x:Static TabControl.HeaderSelector}"
                       Items="{TemplateBinding Items}"
                       SelectedIndex="{TemplateBinding Path=SelectedIndex, Mode=TwoWay}"/>
             <Carousel Name="PART_Content"
-                      MemberSelector="{Static TabControl.ContentSelector}"
+                      MemberSelector="{x:Static TabControl.ContentSelector}"
                       Items="{TemplateBinding Items}"
                       SelectedIndex="{TemplateBinding Path=SelectedIndex}"
                       Transition="{TemplateBinding Transition}"

src/Avalonia.Themes.Default/TextBox.xaml

@@ -1,4 +1,4 @@
-<Styles xmlns="https://github.com/avaloniaui">
+<Styles xmlns="https://github.com/avaloniaui" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <Style Selector="TextBox">
     <Setter Property="Background" Value="{DynamicResource ThemeBackgroundBrush}"/>
     <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderMidBrush}"/>
@@ -18,12 +18,12 @@
                        Text="{TemplateBinding Watermark}"
                        DockPanel.Dock="Top">
               <TextBlock.IsVisible>
-                <MultiBinding Converter="{Static BoolConverters.And}">
+                <MultiBinding Converter="{x:Static BoolConverters.And}">
                   <Binding RelativeSource="{RelativeSource TemplatedParent}"
                            Path="UseFloatingWatermark"/>
                   <Binding RelativeSource="{RelativeSource TemplatedParent}"
                            Path="Text"
-                           Converter="{Static StringConverters.NotNullOrEmpty}"/>
+                           Converter="{x:Static StringConverters.NotNullOrEmpty}"/>
                 </MultiBinding>
               </TextBlock.IsVisible>
             </TextBlock>
@@ -44,7 +44,7 @@
                 <TextBlock Name="watermark"
                            Opacity="0.5"
                            Text="{TemplateBinding Watermark}"
-                           IsVisible="{TemplateBinding Path=Text, Converter={Static StringConverters.NullOrEmpty}}"/>
+                           IsVisible="{TemplateBinding Path=Text, Converter={x:Static StringConverters.NullOrEmpty}}"/>
                 <TextPresenter Name="PART_TextPresenter"
                                Text="{TemplateBinding Text, Mode=TwoWay}"
                                CaretIndex="{TemplateBinding CaretIndex}"

src/Gtk/Avalonia.Gtk3/Gtk3Platform.cs

@@ -35,6 +35,9 @@ namespace Avalonia.Gtk3
                     X11.XInitThreads();
                 }catch{}
                 Resolver.Resolve();
+                if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+                    using (var backends = new Utf8Buffer("x11"))
+                        Native.GdkSetAllowedBackends?.Invoke(backends);
                 Native.GtkInit(0, IntPtr.Zero);
                 var disp = Native.GdkGetDefaultDisplay();
                 DisplayClassName =

src/Gtk/Avalonia.Gtk3/Interop/Native.cs

@@ -48,10 +48,13 @@ namespace Avalonia.Gtk3.Interop
             public delegate void gtk_main_iteration();
 
             [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gtk)]
-            public delegate GtkWindow gtk_window_new(GtkWindowType windowType);
-
+            public delegate GtkWindow gtk_window_new(GtkWindowType windowType);           
+            
             [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gtk)]
             public delegate IntPtr gtk_init(int argc, IntPtr argv);
+            
+            [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gdk, optional: true)]
+            public delegate IntPtr gdk_set_allowed_backends (Utf8Buffer backends);
 
             [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gtk)]
             public delegate void gtk_window_present(GtkWindow gtkWindow);
@@ -102,6 +105,9 @@ namespace Avalonia.Gtk3.Interop
             
             [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gdk)]
             public delegate void gdk_window_resize(IntPtr gtkWindow, int width, int height);
+            
+            [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gdk)]
+            public delegate void gdk_window_set_override_redirect(IntPtr gdkWindow, bool value);
 
             [UnmanagedFunctionPointer(CallingConvention.Cdecl), GtkImport(GtkDll.Gtk)]
             public delegate void gtk_widget_realize(GtkWidget gtkWidget);
@@ -390,6 +396,7 @@ namespace Avalonia.Gtk3.Interop
         public static D.gtk_window_new GtkWindowNew;
         public static D.gtk_window_set_icon GtkWindowSetIcon;
         public static D.gtk_window_set_modal GtkWindowSetModal;
+        public static D.gdk_set_allowed_backends GdkSetAllowedBackends;
         public static D.gtk_init GtkInit;
         public static D.gtk_window_present GtkWindowPresent;
         public static D.gtk_widget_hide GtkWidgetHide;
@@ -402,6 +409,7 @@ namespace Avalonia.Gtk3.Interop
         public static D.gtk_window_get_size GtkWindowGetSize;
         public static D.gtk_window_resize GtkWindowResize;
         public static D.gdk_window_resize GdkWindowResize;
+        public static D.gdk_window_set_override_redirect GdkWindowSetOverrideRedirect;
         public static D.gtk_widget_set_size_request GtkWindowSetSizeRequest;
         public static D.gtk_window_set_default_size GtkWindowSetDefaultSize;
         public static D.gtk_window_get_position GtkWindowGetPosition;

src/Gtk/Avalonia.Gtk3/PopupImpl.cs

@@ -19,6 +19,7 @@ namespace Avalonia.Gtk3
 
         public PopupImpl() : base(CreateWindow())
         {
+            OverrideRedirect = true;
         }
     }
 }

src/Gtk/Avalonia.Gtk3/WindowBaseImpl.cs

@@ -32,6 +32,7 @@ namespace Avalonia.Gtk3
         private IDeferredRenderOperation _nextRenderOperation;
         private readonly AutoResetEvent _canSetNextOperation = new AutoResetEvent(true);
         internal IntPtr? GdkWindowHandle;
+        private bool _overrideRedirect;
         public WindowBaseImpl(GtkWindow gtkWidget)
         {
             
@@ -69,12 +70,15 @@ namespace Avalonia.Gtk3
         private bool OnConfigured(IntPtr gtkwidget, IntPtr ev, IntPtr userdata)
         {
             int w, h;
-            Native.GtkWindowGetSize(GtkWidget, out w, out h);
-            var size = ClientSize = new Size(w, h);
-            if (_lastSize != size)
+            if (!OverrideRedirect)
             {
-                Resized?.Invoke(size);
-                _lastSize = size;
+                Native.GtkWindowGetSize(GtkWidget, out w, out h);
+                var size = ClientSize = new Size(w, h);
+                if (_lastSize != size)
+                {
+                    Resized?.Invoke(size);
+                    _lastSize = size;
+                }
             }
             var pos = Position;
             if (_lastPosition != pos)
@@ -406,6 +410,28 @@ namespace Avalonia.Gtk3
             if (GtkWidget.IsClosed)
                 return;
             Native.GtkWindowResize(GtkWidget, (int)value.Width, (int)value.Height);
+            if (OverrideRedirect)
+            {
+                var size = ClientSize = value;
+                if (_lastSize != size)
+                {
+                    Resized?.Invoke(size);
+                    _lastSize = size;
+                }
+            }
+        }
+
+        public bool OverrideRedirect
+        {
+            get => _overrideRedirect;
+            set
+            {
+                if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+                {
+                    Native.GdkWindowSetOverrideRedirect(Native.GtkWidgetGetWindow(GtkWidget), value);
+                    _overrideRedirect = value;
+                }
+            }
         }
         
         public IScreenImpl Screen

src/Markup/Avalonia.Markup.Xaml/Avalonia.Markup.Xaml.csproj

@@ -77,9 +77,7 @@
         <Compile Include="MarkupExtensions\StyleResourceExtension.cs" />
         <Compile Include="MarkupExtensions\BindingExtension.cs" />
         <Compile Include="MarkupExtensions\RelativeSourceExtension.cs" />
-        <Compile Include="MarkupExtensions\StaticExtension.cs" />
         <Compile Include="MarkupExtensions\TemplateBindingExtension.cs" />
-        <Compile Include="MarkupExtensions\TypeExtension.cs" />
         <Compile Include="Parsers\SelectorGrammar.cs" />
         <Compile Include="Parsers\SelectorParser.cs" />
         <Compile Include="PortableXaml\AvaloniaTypeAttributeProvider.cs" />

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

@@ -1,25 +0,0 @@
-// Copyright (c) The Avalonia Project. All rights reserved.
-// Licensed under the MIT license. See licence.md file in the project root for full license information.
-
-using System;
-
-namespace Avalonia.Markup.Xaml.MarkupExtensions
-{
-    public class StaticExtension : Portable.Xaml.Markup.StaticExtension
-    {
-        public StaticExtension()
-        {
-        }
-
-        public StaticExtension(string member)
-            : base(member)
-        {
-        }
-
-        public override object ProvideValue(IServiceProvider serviceProvider)
-        {
-            return base.ProvideValue(serviceProvider);
-        }
-    }
-    
-}

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

@@ -1,23 +0,0 @@
-// Copyright (c) The Avalonia Project. All rights reserved.
-// Licensed under the MIT license. See licence.md file in the project root for full license information.
-
-using System;
-
-namespace Avalonia.Markup.Xaml.MarkupExtensions
-{
-    public class TypeExtension : Portable.Xaml.Markup.TypeExtension
-    {
-        public TypeExtension()
-        {
-        }
-
-        public TypeExtension(string typeName) : base(typeName)
-        {
-        }
-
-        public override object ProvideValue(IServiceProvider serviceProvider)
-        {
-            return base.ProvideValue(serviceProvider);
-        }
-    }
-}

src/Markup/Avalonia.Markup.Xaml/PortableXaml/AvaloniaXamlType.cs

@@ -135,6 +135,8 @@ namespace Avalonia.Markup.Xaml.PortableXaml
             };
         }
 
+        protected override bool LookupIsUnknown() => false;
+
         protected override XamlType LookupType()
         {
             var propType = GetPropertyType();
@@ -294,8 +296,6 @@ namespace Avalonia.Markup.Xaml.PortableXaml
             return Property.IsReadOnly;
         }
 
-        protected override bool LookupIsUnknown() => false;
-
         protected override Type GetPropertyType()
         {
             return Property.PropertyType;

tests/Avalonia.Controls.UnitTests/ControlTests.cs

@@ -8,6 +8,7 @@ using Moq;
 using Avalonia.Styling;
 using Avalonia.UnitTests;
 using Xunit;
+using Avalonia.LogicalTree;
 
 namespace Avalonia.Controls.UnitTests
 {
@@ -328,9 +329,139 @@ namespace Avalonia.Controls.UnitTests
             Assert.True(target.IsInitialized);
         }
 
-        private class TestControl : Control
+        [Fact]
+        public void DataContextChanged_Should_Be_Called()
+        {
+            var root = new TestStackPanel
+            {
+                Name = "root",
+                Children =
+                {
+                    new TestControl
+                    {
+                        Name = "a1",
+                        Child = new TestControl
+                        {
+                            Name = "b1",
+                        }
+                    },
+                    new TestControl
+                    {
+                        Name = "a2",
+                        DataContext = "foo",
+                    },
+                }
+            };
+
+            var called = new List<string>();
+            void Record(object sender, EventArgs e) => called.Add(((Control)sender).Name);
+
+            root.DataContextChanged += Record;
+
+            foreach (TestControl c in root.GetLogicalDescendants())
+            {
+                c.DataContextChanged += Record;
+            }
+
+            root.DataContext = "foo";
+
+            Assert.Equal(new[] { "root", "a1", "b1", }, called);
+        }
+
+        [Fact]
+        public void DataContext_Notifications_Should_Be_Called_In_Correct_Order()
         {
+            var root = new TestStackPanel
+            {
+                Name = "root",
+                Children =
+                {
+                    new TestControl
+                    {
+                        Name = "a1",
+                        Child = new TestControl
+                        {
+                            Name = "b1",
+                        }
+                    },
+                    new TestControl
+                    {
+                        Name = "a2",
+                        DataContext = "foo",
+                    },
+                }
+            };
+
+            var called = new List<string>();
+
+            foreach (IDataContextEvents c in root.GetSelfAndLogicalDescendants())
+            {
+                c.DataContextBeginUpdate += (s, e) => called.Add("begin " + ((Control)s).Name);
+                c.DataContextChanged += (s, e) => called.Add("changed " + ((Control)s).Name);
+                c.DataContextEndUpdate += (s, e) => called.Add("end " + ((Control)s).Name);
+            }
+
+            root.DataContext = "foo";
+
+            Assert.Equal(
+                new[] 
+                {
+                    "begin root",
+                    "begin a1",
+                    "begin b1",
+                    "changed root",
+                    "changed a1",
+                    "changed b1",
+                    "end b1",
+                    "end a1",
+                    "end root",
+                },
+                called);
+        }
+
+        private interface IDataContextEvents
+        {
+            event EventHandler DataContextBeginUpdate;
+            event EventHandler DataContextChanged;
+            event EventHandler DataContextEndUpdate;
+        }
+
+        private class TestControl : Decorator, IDataContextEvents
+        {
+            public event EventHandler DataContextBeginUpdate;
+            public event EventHandler DataContextEndUpdate;
+
             public new IAvaloniaObject InheritanceParent => base.InheritanceParent;
+
+            protected override void OnDataContextBeginUpdate()
+            {
+                DataContextBeginUpdate?.Invoke(this, EventArgs.Empty);
+                base.OnDataContextBeginUpdate();
+            }
+
+            protected override void OnDataContextEndUpdate()
+            {
+                DataContextEndUpdate?.Invoke(this, EventArgs.Empty);
+                base.OnDataContextEndUpdate();
+            }
+        }
+
+        private class TestStackPanel : StackPanel, IDataContextEvents
+        {
+            public event EventHandler DataContextBeginUpdate;
+            public event EventHandler DataContextEndUpdate;
+
+            protected override void OnDataContextBeginUpdate()
+            {
+                DataContextBeginUpdate?.Invoke(this, EventArgs.Empty);
+                base.OnDataContextBeginUpdate();
+            }
+
+            protected override void OnDataContextEndUpdate()
+            {
+                DataContextEndUpdate?.Invoke(this, EventArgs.Empty);
+                base.OnDataContextEndUpdate();
+            }
         }
     }
 }

tests/Avalonia.Markup.UnitTests/Data/Plugins/DataAnnotationsValidationPluginTests.cs

@@ -49,6 +49,8 @@ namespace Avalonia.Markup.UnitTests.Data.Plugins
             var accessor = inpcAccessorPlugin.Start(new WeakReference(data), nameof(data.Between5And10));
             var validator = validatorPlugin.Start(new WeakReference(data), nameof(data.Between5And10), accessor);
             var result = new List<object>();
+            
+            var errmsg = new RangeAttribute(5, 10).FormatErrorMessage(nameof(Data.Between5And10));
 
             validator.Subscribe(x => result.Add(x));
             validator.SetValue(3, BindingPriority.LocalValue);
@@ -59,12 +61,12 @@ namespace Avalonia.Markup.UnitTests.Data.Plugins
             {
                 new BindingNotification(5),
                 new BindingNotification(
-                    new ValidationException("The field Between5And10 must be between 5 and 10."),
+                    new ValidationException(errmsg),
                     BindingErrorType.DataValidationError,
                     3),
                 new BindingNotification(7),
                 new BindingNotification(
-                    new ValidationException("The field Between5And10 must be between 5 and 10."),
+                    new ValidationException(errmsg),
                     BindingErrorType.DataValidationError,
                     11),
             }, result);

tests/Avalonia.Markup.Xaml.UnitTests/Xaml/BasicTests.cs

@@ -609,8 +609,8 @@ namespace Avalonia.Markup.Xaml.UnitTests.Xaml
         public void Multi_Xaml_Binding_Is_Parsed()
         {
             var xaml =
-@"<MultiBinding xmlns='https://github.com/avaloniaui'
-        Converter='{Static BoolConverters.And}'>
+@"<MultiBinding xmlns='https://github.com/avaloniaui' xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
+    Converter ='{x:Static BoolConverters.And}'>
      <Binding Path='Foo' />
      <Binding Path='Bar' />
 </MultiBinding>";
@@ -818,10 +818,11 @@ do we need it?")]
         {
             var xaml =
 @"<ContentControl xmlns='https://github.com/avaloniaui'
+            xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
             xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests.Xaml;assembly=Avalonia.Markup.Xaml.UnitTests'>
     <ContentControl.ContentTemplate>
         <DataTemplate>
-            <TextBlock  Tag='{Static local:NonControl.StringProperty}'/>
+            <TextBlock  Tag='{x:Static local:NonControl.StringProperty}'/>
         </DataTemplate>
     </ContentControl.ContentTemplate>
 </ContentControl>";

tests/Avalonia.Markup.Xaml.UnitTests/Xaml/ControlBindingTests.cs

@@ -1,7 +1,10 @@
 // Copyright (c) The Avalonia Project. All rights reserved.
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
+using System.Collections.Generic;
 using Avalonia.Controls;
+using Avalonia.Controls.Primitives;
+using Avalonia.Layout;
 using Avalonia.Logging;
 using Avalonia.UnitTests;
 using Xunit;
@@ -67,5 +70,61 @@ namespace Avalonia.Markup.Xaml.UnitTests.Xaml
                 Assert.True(called);
             }
         }
+
+        [Fact]
+        public void Can_Bind_Between_TabStrip_And_Carousel()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            {
+                var xaml = @"
+<Window xmlns='https://github.com/avaloniaui'>
+    <DockPanel>
+        <TabStrip Name='strip' DockPanel.Dock='Top' Items='{Binding Items}' SelectedIndex='0'>
+          <TabStrip.DataTemplates>
+            <DataTemplate>
+              <TextBlock Text='{Binding Header}'/>
+            </DataTemplate>
+          </TabStrip.DataTemplates>
+        </TabStrip>
+        <Carousel Name='carousel' Items='{Binding Items}' SelectedIndex='{Binding #strip.SelectedIndex}'>
+          <Carousel.DataTemplates>
+            <DataTemplate>
+              <TextBlock Text='{Binding Detail}'/>
+            </DataTemplate>
+          </Carousel.DataTemplates>
+        </Carousel>
+    </DockPanel>
+</Window>";
+                var loader = new AvaloniaXamlLoader();
+                var window = (Window)loader.Load(xaml);
+                var strip = window.FindControl<TabStrip>("strip");
+                var carousel = window.FindControl<Carousel>("carousel");
+
+                window.DataContext = new ItemsViewModel
+                {
+                    Items = new[]
+                    {
+                        new ItemViewModel { Header = "Item1", Detail = "Detail1" },
+                        new ItemViewModel { Header = "Item2", Detail = "Detail2" },
+                    }
+                };
+
+                window.Show();
+
+                Assert.Equal(0, strip.SelectedIndex);
+                Assert.Equal(0, carousel.SelectedIndex);
+            }
+        }
+
+        private class ItemsViewModel
+        {
+            public IList<ItemViewModel> Items { get; set; }
+        }
+
+        private class ItemViewModel
+        {
+            public string Header { get; set; }
+            public string Detail { get; set; }
+        }
     }
 }

tests/Avalonia.Markup.Xaml.UnitTests/Xaml/DataTemplateTests.cs

@@ -17,9 +17,10 @@ namespace Avalonia.Markup.Xaml.UnitTests.Xaml
             {
                 var xaml = @"
 <Window xmlns='https://github.com/avaloniaui'
-        xmlns:sys='clr-namespace:System;assembly=mscorlib'>
+        xmlns:sys='clr-namespace:System;assembly=mscorlib'
+        xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'>
     <Window.DataTemplates>
-        <DataTemplate DataType='{Type sys:String}'>
+        <DataTemplate DataType='{x:Type sys:String}'>
             <Canvas Name='foo'/>
         </DataTemplate>
     </Window.DataTemplates>
@@ -43,10 +44,10 @@ namespace Avalonia.Markup.Xaml.UnitTests.Xaml
             using (UnitTestApplication.Start(TestServices.StyledWindow))
             {
                 var xaml = @"
-<Window xmlns='https://github.com/avaloniaui'
+<Window xmlns='https://github.com/avaloniaui' xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'
         xmlns:local='clr-namespace:Avalonia.Markup.Xaml.UnitTests;assembly=Avalonia.Markup.Xaml.UnitTests'>
     <Window.DataTemplates>
-        <DataTemplate DataType='{Type local:TestViewModel}'>
+        <DataTemplate DataType='{x:Type local:TestViewModel}'>
             <Canvas Name='foo' DataContext='{Binding Child}'/>
         </DataTemplate>
     </Window.DataTemplates>

tests/Avalonia.Styling.UnitTests/SetterTests.cs

@@ -8,6 +8,9 @@ using Avalonia.Data;
 using Xunit;
 using System;
 using Avalonia.Controls.Templates;
+using Avalonia.Markup.Xaml.Data;
+using Avalonia.Markup;
+using System.Globalization;
 
 namespace Avalonia.Styling.UnitTests
 {
@@ -61,5 +64,39 @@ namespace Avalonia.Styling.UnitTests
 
             Assert.NotNull(NameScope.GetNameScope((Control)control.Child));
         }
+
+        [Fact]
+        public void Does_Not_Call_Converter_ConvertBack_On_OneWay_Binding()
+        {
+            var control = new Decorator { Name = "foo" };
+            var style = Mock.Of<IStyle>();
+            var binding = new Binding("Name", BindingMode.OneWay)
+            {
+                Converter = new TestConverter(),
+                RelativeSource = new RelativeSource(RelativeSourceMode.Self),
+            };
+            var setter = new Setter(Decorator.TagProperty, binding);
+            var activator = new BehaviorSubject<bool>(true);
+
+            setter.Apply(style, control, activator);
+            Assert.Equal("foobar", control.Tag);
+
+            // Issue #1218 caused TestConverter.ConvertBack to throw here.
+            activator.OnNext(false);
+            Assert.Null(control.Tag);
+        }
+
+        private class TestConverter : IValueConverter
+        {
+            public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+            {
+                return value.ToString() + "bar";
+            }
+
+            public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+            {
+                throw new NotImplementedException();
+            }
+        }
     }
 }