Create DataGrid Fluent.xaml theme based on Default

samples/ControlCatalog/App.xaml

@@ -1,8 +1,7 @@
 <Application xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              x:Class="ControlCatalog.App">
-  <Application.Styles>        
-    <StyleInclude Source="avares://Avalonia.Controls.DataGrid/Themes/Default.xaml"/>
+  <Application.Styles>
     <Style Selector="TextBlock.h1">
       <Setter Property="FontSize" Value="16" />
       <Setter Property="FontWeight" Value="Medium" />

samples/ControlCatalog/App.xaml.cs

@@ -9,12 +9,23 @@ namespace ControlCatalog
 {
     public class App : Application
     {
+        private static readonly StyleInclude DataGridFluent = new StyleInclude(new Uri("avares://ControlCatalog/Styles"))
+        {
+            Source = new Uri("avares://Avalonia.Controls.DataGrid/Themes/Fluent.xaml")
+        };
+
+        private static readonly StyleInclude DataGridDefault = new StyleInclude(new Uri("avares://ControlCatalog/Styles"))
+        {
+            Source = new Uri("avares://Avalonia.Controls.DataGrid/Themes/Default.xaml")
+        };
+
         public static Styles FluentDark = new Styles
         {
             new StyleInclude(new Uri("avares://ControlCatalog/Styles"))
             {
                 Source = new Uri("avares://Avalonia.Themes.Fluent/Accents/FluentDark.xaml")
             },
+            DataGridFluent
         };
 
         public static Styles FluentLight = new Styles
@@ -23,6 +34,7 @@ namespace ControlCatalog
             {
                 Source = new Uri("avares://Avalonia.Themes.Fluent/Accents/FluentLight.xaml")
             },
+            DataGridFluent
         };
 
         public static Styles DefaultLight = new Styles
@@ -43,6 +55,7 @@ namespace ControlCatalog
             {
                 Source = new Uri("avares://Avalonia.Themes.Default/DefaultTheme.xaml")
             },
+            DataGridDefault
         };
 
         public static Styles DefaultDark = new Styles
@@ -63,6 +76,7 @@ namespace ControlCatalog
             {
                 Source = new Uri("avares://Avalonia.Themes.Default/DefaultTheme.xaml")
             },
+            DataGridDefault
         };
 
         public override void Initialize()

src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml

@@ -0,0 +1,294 @@
+<Styles xmlns="https://github.com/avaloniaui">
+  <!--  TODO: Validation and Focus  -->
+  <Style Selector="DataGridCell">
+    <Setter Property="Background" Value="Transparent" />
+    <Setter Property="HorizontalContentAlignment" Value="Stretch" />
+    <Setter Property="VerticalContentAlignment" Value="Stretch" />
+    <Setter Property="Template">
+      <ControlTemplate>
+        <Grid ColumnDefinitions="*,Auto"
+              Background="{TemplateBinding Background}">
+          <ContentPresenter ContentTemplate="{TemplateBinding ContentTemplate}"
+                            Content="{TemplateBinding Content}"
+                            Margin="{TemplateBinding Padding}"
+                            TextBlock.Foreground="{TemplateBinding Foreground}"
+                            HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
+                            VerticalAlignment="{TemplateBinding VerticalContentAlignment}" />
+
+          <Rectangle Name="PART_RightGridLine"
+                     Grid.Column="1"
+                     VerticalAlignment="Stretch"
+                     Width="1" />
+        </Grid>
+      </ControlTemplate>
+    </Setter>
+  </Style>
+
+  <Style Selector="DataGridColumnHeader">
+    <Setter Property="Foreground" Value="{DynamicResource ThemeForegroundBrush}" />
+    <Setter Property="HorizontalContentAlignment" Value="Left" />
+    <Setter Property="VerticalContentAlignment" Value="Center" />
+    <Setter Property="SeparatorBrush" Value="{DynamicResource ThemeControlLowColor}" />
+    <Setter Property="Padding" Value="4" />
+    <Setter Property="Background" Value="{DynamicResource ThemeControlMidBrush}" />
+
+    <Setter Property="Template">
+      <ControlTemplate>
+        <Grid ColumnDefinitions="*,Auto"
+              Background="{TemplateBinding Background}">
+
+          <Grid ColumnDefinitions="*,Auto"
+                HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
+                VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
+                Margin="{TemplateBinding Padding}">
+            <ContentPresenter Content="{TemplateBinding Content}" />
+
+            <Path Name="SortIcon"
+                  Grid.Column="1"
+                  Fill="{TemplateBinding Foreground}"
+                  HorizontalAlignment="Left"
+                  VerticalAlignment="Center"
+                  Stretch="Uniform"
+                  Width="8"
+                  Margin="4,0,0,0"
+                  Data="F1 M -5.215,6.099L 5.215,6.099L 0,0L -5.215,6.099 Z " />
+
+          </Grid>
+
+          <Rectangle Name="VerticalSeparator"
+                     Grid.Column="1"
+                     Width="1"
+                     VerticalAlignment="Stretch"
+                     Fill="{TemplateBinding SeparatorBrush}"
+                     IsVisible="{TemplateBinding AreSeparatorsVisible}" />
+
+        </Grid>
+      </ControlTemplate>
+    </Setter>
+  </Style>
+
+  <Style Selector="DataGridColumnHeader:dragIndicator">
+    <Setter Property="Opacity" Value="0.5" />
+  </Style>
+
+  <Style Selector="DataGridColumnHeader /template/ Path#SortIcon">
+    <Setter Property="IsVisible" Value="False" />
+    <Setter Property="RenderTransform">
+      <Setter.Value>
+        <ScaleTransform ScaleX="0.9"
+                        ScaleY="0.9" />
+      </Setter.Value>
+    </Setter>
+  </Style>
+
+  <Style Selector="DataGridColumnHeader:sortascending /template/ Path#SortIcon">
+    <Setter Property="IsVisible" Value="True" />
+  </Style>
+
+  <Style Selector="DataGridColumnHeader:sortdescending /template/ Path#SortIcon">
+    <Setter Property="IsVisible" Value="True" />
+    <Setter Property="RenderTransform">
+      <Setter.Value>
+        <ScaleTransform ScaleX="0.9"
+                        ScaleY="-0.9" />
+      </Setter.Value>
+    </Setter>
+  </Style>
+
+  <Style Selector="DataGridRow">
+    <Setter Property="Template">
+      <ControlTemplate>
+        <DataGridFrozenGrid Name="PART_Root"
+                            RowDefinitions="*,Auto,Auto"
+                            ColumnDefinitions="Auto,*">
+
+          <Rectangle Name="BackgroundRectangle"
+                     Grid.RowSpan="2"
+                     Grid.ColumnSpan="2" />
+
+          <DataGridRowHeader Grid.RowSpan="3"
+                             Name="PART_RowHeader"
+                             DataGridFrozenGrid.IsFrozen="True" />
+          <DataGridCellsPresenter Grid.Column="1"
+                                  Name="PART_CellsPresenter"
+                                  DataGridFrozenGrid.IsFrozen="True" />
+          <DataGridDetailsPresenter Grid.Row="1"
+                                    Grid.Column="1"
+                                    Name="PART_DetailsPresenter" />
+          <Rectangle Grid.Row="2"
+                     Grid.Column="1"
+                     Name="PART_BottomGridLine"
+                     HorizontalAlignment="Stretch"
+                     Height="1" />
+
+        </DataGridFrozenGrid>
+      </ControlTemplate>
+    </Setter>
+  </Style>
+
+  <Style Selector="DataGridRow /template/ Rectangle#BackgroundRectangle">
+    <Setter Property="IsVisible" Value="False" />
+    <Setter Property="Fill" Value="{DynamicResource HighlightBrush}" />
+  </Style>
+
+  <Style Selector="DataGridRow:pointerover /template/ Rectangle#BackgroundRectangle">
+    <Setter Property="IsVisible" Value="True" />
+    <Setter Property="Opacity" Value="0.5" />
+  </Style>
+
+  <Style Selector="DataGridRow:selected /template/ Rectangle#BackgroundRectangle">
+    <Setter Property="IsVisible" Value="True" />
+    <Setter Property="Opacity" Value="1" />
+  </Style>
+
+  <Style Selector="DataGridRow:selected">
+    <Setter Property="Foreground" Value="{DynamicResource HighlightForegroundBrush}" />
+  </Style>
+
+  <Style Selector="DataGridRowHeader">
+    <Setter Property="Template">
+      <ControlTemplate>
+        <Grid RowDefinitions="*,*,Auto"
+              ColumnDefinitions="Auto,*" />
+      </ControlTemplate>
+    </Setter>
+  </Style>
+
+  <Style Selector="DataGridRowGroupHeader">
+    <Setter Property="Background" Value="{DynamicResource ThemeControlMidHighBrush}" />
+    <Setter Property="Height" Value="20" />
+    <Setter Property="Template">
+      <ControlTemplate>
+        <DataGridFrozenGrid Name="Root"
+                            Background="{TemplateBinding Background}"
+                            ColumnDefinitions="Auto,Auto,Auto,Auto"
+                            RowDefinitions="Auto,*,Auto">
+
+          <Rectangle Grid.Column="1"
+                     Grid.Row="1"
+                     Name="IndentSpacer" />
+          <ToggleButton Grid.Column="2"
+                        Grid.Row="1"
+                        Name="ExpanderButton"
+                        Margin="2,0,0,0" />
+
+          <StackPanel Grid.Column="3"
+                      Grid.Row="1"
+                      Orientation="Horizontal"
+                      VerticalAlignment="Center"
+                      Margin="0,1,0,1">
+            <TextBlock Name="PropertyNameElement"
+                       Margin="4,0,0,0"
+                       IsVisible="{TemplateBinding IsPropertyNameVisible}" />
+            <TextBlock Margin="4,0,0,0"
+                       Text="{Binding Key}" />
+            <TextBlock Name="ItemCountElement"
+                       Margin="4,0,0,0"
+                       IsVisible="{TemplateBinding IsItemCountVisible}" />
+          </StackPanel>
+
+          <DataGridRowHeader Name="RowHeader"
+                             Grid.RowSpan="3"
+                             DataGridFrozenGrid.IsFrozen="True" />
+
+        </DataGridFrozenGrid>
+      </ControlTemplate>
+    </Setter>
+  </Style>
+
+  <Style Selector="DataGridRowGroupHeader /template/ ToggleButton#ExpanderButton">
+    <Setter Property="Template">
+      <ControlTemplate>
+        <Border Grid.Column="0"
+                Width="20"
+                Height="20"
+                Background="Transparent"
+                HorizontalAlignment="Center"
+                VerticalAlignment="Center">
+          <Path Fill="{TemplateBinding Foreground}"
+                HorizontalAlignment="Center"
+                VerticalAlignment="Center"
+                Data="M 0 2 L 4 6 L 0 10 Z" />
+        </Border>
+      </ControlTemplate>
+    </Setter>
+  </Style>
+
+  <Style Selector="DataGridRowGroupHeader /template/ ToggleButton#ExpanderButton:checked /template/ Path">
+    <Setter Property="RenderTransform">
+      <RotateTransform Angle="90" />
+    </Setter>
+  </Style>
+
+  <Style Selector="DataGrid">
+    <Setter Property="RowBackground" Value="{DynamicResource ThemeAccentBrush4}" />
+    <Setter Property="AlternatingRowBackground" Value="#00FFFFFF" />
+    <Setter Property="Background" Value="{DynamicResource ThemeBackgroundBrush}" />
+    <Setter Property="HeadersVisibility" Value="Column" />
+    <Setter Property="HorizontalScrollBarVisibility" Value="Auto" />
+    <Setter Property="VerticalScrollBarVisibility" Value="Auto" />
+    <Setter Property="SelectionMode" Value="Extended" />
+    <Setter Property="GridLinesVisibility" Value="Vertical" />
+    <Setter Property="HorizontalGridLinesBrush" Value="{DynamicResource ThemeBorderHighColor}" />
+    <Setter Property="VerticalGridLinesBrush" Value="{DynamicResource ThemeBorderHighColor}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderLowColor}" />
+    <Setter Property="BorderThickness" Value="{DynamicResource ThemeBorderThickness}" />
+    <Setter Property="DropLocationIndicatorTemplate">
+      <Template>
+        <Rectangle Fill="{DynamicResource ThemeBorderHighColor}"
+                   Width="2" />
+      </Template>
+    </Setter>
+    <Setter Property="Template">
+      <ControlTemplate>
+        <Border Background="{TemplateBinding Background}"
+                BorderThickness="{TemplateBinding BorderThickness}"
+                BorderBrush="{TemplateBinding BorderBrush}">
+          <Grid RowDefinitions="Auto,*,Auto,Auto"
+                ColumnDefinitions="Auto,*,Auto">
+
+            <DataGridColumnHeader Name="PART_TopLeftCornerHeader"
+                                  Width="22" />
+            <DataGridColumnHeadersPresenter Name="PART_ColumnHeadersPresenter"
+                                            Grid.Column="1" />
+            <DataGridColumnHeader Name="PART_TopRightCornerHeader"
+                                  Grid.Column="2" />
+            <Rectangle Name="PART_ColumnHeadersAndRowsSeparator"
+                       Grid.ColumnSpan="3"
+                       VerticalAlignment="Bottom"
+                       StrokeThickness="1"
+                       Height="1"
+                       Fill="{DynamicResource ThemeControlMidHighBrush}" />
+
+            <DataGridRowsPresenter Name="PART_RowsPresenter"
+                                   Grid.ColumnSpan="2"
+                                   Grid.Row="1" />
+            <Rectangle Name="BottomRightCorner"
+                       Fill="{DynamicResource ThemeControlMidHighBrush}"
+                       Grid.Column="2"
+                       Grid.Row="2" />
+            <Rectangle Name="BottomLeftCorner"
+                       Fill="{DynamicResource ThemeControlMidHighBrush}"
+                       Grid.Row="2"
+                       Grid.ColumnSpan="2" />
+            <ScrollBar Name="PART_VerticalScrollbar"
+                       Orientation="Vertical"
+                       Grid.Column="2"
+                       Grid.Row="1"
+                       Width="{DynamicResource ScrollBarThickness}" />
+
+            <Grid Grid.Column="1"
+                  Grid.Row="2"
+                  ColumnDefinitions="Auto,*">
+              <Rectangle Name="PART_FrozenColumnScrollBarSpacer" />
+              <ScrollBar Name="PART_HorizontalScrollbar"
+                         Grid.Column="1"
+                         Orientation="Horizontal"
+                         Height="{DynamicResource ScrollBarThickness}" />
+            </Grid>
+          </Grid>
+        </Border>
+      </ControlTemplate>
+    </Setter>
+  </Style>
+</Styles>