Merge branch 'master' into fixes/4781-treeview-setting-bound-selected-item-null

src/Avalonia.Controls/Presenters/ContentPresenter.cs

@@ -1,9 +1,9 @@
 using System;
+
+using Avalonia.Controls.Metadata;
 using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Templates;
 using Avalonia.Controls.Utils;
-using Avalonia.Data;
-using Avalonia.Input;
 using Avalonia.Layout;
 using Avalonia.LogicalTree;
 using Avalonia.Media;
@@ -14,6 +14,7 @@ namespace Avalonia.Controls.Presenters
     /// <summary>
     /// Presents a single item of data inside a <see cref="TemplatedControl"/> template.
     /// </summary>
+    [PseudoClasses(":empty")]
     public class ContentPresenter : Control, IContentPresenter
     {
         /// <summary>
@@ -102,6 +103,11 @@ namespace Avalonia.Controls.Presenters
             TemplatedParentProperty.Changed.AddClassHandler<ContentPresenter>((x, e) => x.TemplatedParentChanged(e));
         }
 
+        public ContentPresenter()
+        {
+            UpdatePseudoClasses();
+        }
+
         /// <summary>
         /// Gets or sets a brush with which to paint the background.
         /// </summary>
@@ -424,9 +430,15 @@ namespace Avalonia.Controls.Presenters
                 _recyclingDataTemplate = null;
             }
 
+            UpdatePseudoClasses();
             InvalidateMeasure();
         }
 
+        private void UpdatePseudoClasses()
+        {
+            PseudoClasses.Set(":empty", Content is null);
+        }
+
         private double GetLayoutScale()
         {
             var result = (VisualRoot as ILayoutRoot)?.LayoutScaling ?? 1.0;

src/Avalonia.Themes.Default/ToggleSwitch.xaml

@@ -87,7 +87,6 @@
             Grid.Row="0"
             Content="{TemplateBinding Content}"
             ContentTemplate="{TemplateBinding ContentTemplate}"
-            Margin="{DynamicResource ToggleSwitchTopHeaderMargin}"
             VerticalAlignment="Top"/>
 
           <Grid Grid.Row="1"
@@ -163,6 +162,13 @@
     </Setter>
   </Style>
 
+  <Style Selector="ToggleSwitch /template/ ContentPresenter#PART_ContentPresenter">
+    <Setter Property="Margin" Value="{DynamicResource ToggleSwitchTopHeaderMargin}" />
+  </Style>
+  <Style Selector="ToggleSwitch /template/ ContentPresenter#PART_ContentPresenter:empty">
+    <Setter Property="Margin" Value="0" />
+  </Style>
+
   <!-- NormalState -->
   <Style Selector="ToggleSwitch /template/ Grid#SwitchAreaGrid">
     <Setter Property="Background" Value="{DynamicResource ToggleSwitchContainerBackground}"/>

src/Avalonia.Themes.Fluent/DataValidationErrors.xaml

@@ -31,12 +31,16 @@
   </Setter>
   <Setter Property="ErrorTemplate">
     <DataTemplate>
-      <Canvas Width="14" Height="14" Margin="4 0 1 0" 
+      <Canvas Name="PART_ErrorTemplateCanvas"
+              Width="14" Height="14" Margin="4 0 1 0" 
               Background="Transparent">
         <Canvas.Styles>
-          <Style Selector="ToolTip">
+          <Style Selector="Canvas#PART_ErrorTemplateCanvas ToolTip">
             <Setter Property="BorderBrush" Value="{DynamicResource SystemControlErrorTextForegroundBrush}"/>
           </Style>
+          <Style Selector="Canvas#PART_ErrorTemplateCanvas ToolTip TextBlock">
+            <Setter Property="TextWrapping" Value="Wrap" />
+          </Style>
         </Canvas.Styles>
         <ToolTip.Tip>
           <ItemsControl Items="{Binding}"/>

src/Avalonia.Themes.Fluent/ToggleSwitch.xaml

@@ -31,7 +31,7 @@
           Text="The previewer Shows a preview off your code, this could slow down your system"
           TextWrapping="Wrap"/>
         <ToggleSwitch
-          Content="Previewer"
+          Background="Green"
           IsChecked="True" />
       </StackPanel>
     </StackPanel>
@@ -53,7 +53,6 @@
             Grid.Row="0"
             Content="{TemplateBinding Content}"
             ContentTemplate="{TemplateBinding ContentTemplate}"
-            Margin="{DynamicResource ToggleSwitchTopHeaderMargin}"
             VerticalAlignment="Top"/>
 
           <Grid Grid.Row="1"
@@ -129,6 +128,13 @@
     </Setter>
   </Style>
 
+  <Style Selector="ToggleSwitch /template/ ContentPresenter#PART_ContentPresenter">
+    <Setter Property="Margin" Value="{DynamicResource ToggleSwitchTopHeaderMargin}" />
+  </Style>
+  <Style Selector="ToggleSwitch /template/ ContentPresenter#PART_ContentPresenter:empty">
+    <Setter Property="Margin" Value="0" />
+  </Style>
+
   <!-- NormalState -->
   <Style Selector="ToggleSwitch /template/ Grid#SwitchAreaGrid">
     <Setter Property="Background" Value="{DynamicResource ToggleSwitchContainerBackground}"/>