From fe6a735c6f375cf985a36cd8135efd88cc991c54 Mon Sep 17 00:00:00 2001
From: Maksym Katsydan <maxkatz6@outlook.com>
Date: Tue, 18 Aug 2020 14:11:41 -0400
Subject: [PATCH 1/8] Create DataGrid Fluent.xaml theme based on Default

---
 samples/ControlCatalog/App.xaml               |   3 +-
 samples/ControlCatalog/App.xaml.cs            |  14 +
 .../Themes/Fluent.xaml                        | 294 ++++++++++++++++++
 3 files changed, 309 insertions(+), 2 deletions(-)
 create mode 100644 src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml

diff --git a/samples/ControlCatalog/App.xaml b/samples/ControlCatalog/App.xaml
index bab57f3544..9bac320c79 100644
--- a/samples/ControlCatalog/App.xaml
+++ b/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" />
diff --git a/samples/ControlCatalog/App.xaml.cs b/samples/ControlCatalog/App.xaml.cs
index b0fbcc76d2..cb50cba540 100644
--- a/samples/ControlCatalog/App.xaml.cs
+++ b/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()
diff --git a/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml b/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
new file mode 100644
index 0000000000..a32989372c
--- /dev/null
+++ b/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>

From 60546c68de3b9c4549a37c33d9c00494377de0df Mon Sep 17 00:00:00 2001
From: Maksym Katsydan <maxkatz6@outlook.com>
Date: Thu, 20 Aug 2020 02:13:17 -0400
Subject: [PATCH 2/8] DataGrid: implement missed pseudoclasses

---
 src/Avalonia.Controls.DataGrid/DataGrid.cs    |  4 ++--
 .../DataGridCell.cs                           | 11 ++++++++++
 .../DataGridColumnHeader.cs                   | 13 ++++++------
 .../DataGridDataConnection.cs                 |  2 +-
 src/Avalonia.Controls.DataGrid/DataGridRow.cs |  8 +++----
 .../DataGridRowGroupHeader.cs                 | 20 +++++++++++-------
 .../DataGridRowHeader.cs                      | 21 ++++++++++++++++---
 .../DataGridRows.cs                           |  2 +-
 8 files changed, 57 insertions(+), 24 deletions(-)

diff --git a/src/Avalonia.Controls.DataGrid/DataGrid.cs b/src/Avalonia.Controls.DataGrid/DataGrid.cs
index 7e921944ea..78c696a3ba 100644
--- a/src/Avalonia.Controls.DataGrid/DataGrid.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGrid.cs
@@ -2753,7 +2753,7 @@ namespace Avalonia.Controls
                         //We don't need to refresh the state of AutoGenerated column headers because they're up-to-date
                         if (!column.IsAutoGenerated && column.HasHeaderCell)
                         {
-                            column.HeaderCell.ApplyState();
+                            column.HeaderCell.UpdatePseudoClasses();
                         }
                     }
 
@@ -5417,7 +5417,7 @@ namespace Avalonia.Controls
             }
             else if (displayedElement is DataGridRowGroupHeader groupHeader)
             {
-                groupHeader.ApplyState(useTransitions: true);
+                groupHeader.UpdatePseudoClasses();
                 if (AreRowHeadersVisible)
                 {
                     groupHeader.ApplyHeaderStatus();
diff --git a/src/Avalonia.Controls.DataGrid/DataGridCell.cs b/src/Avalonia.Controls.DataGrid/DataGridCell.cs
index 3973f1e86f..99efc5743d 100644
--- a/src/Avalonia.Controls.DataGrid/DataGridCell.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGridCell.cs
@@ -180,7 +180,18 @@ namespace Avalonia.Controls
 
         internal void UpdatePseudoClasses()
         {
+            if (OwningGrid == null || OwningColumn == null || OwningRow == null || !OwningRow.IsVisible || OwningRow.Slot == -1)
+            {
+                return;
+            }
+
+            PseudoClasses.Set(":selected", OwningRow.IsSelected);
+
+            PseudoClasses.Set(":current", IsCurrent);
+
+            PseudoClasses.Set(":edited", IsEdited);
 
+            // PseudoClasses.Set(":invalid", !IsValid);
         }
 
         // Makes sure the right gridline has the proper stroke and visibility. If lastVisibleColumn is specified, the 
diff --git a/src/Avalonia.Controls.DataGrid/DataGridColumnHeader.cs b/src/Avalonia.Controls.DataGrid/DataGridColumnHeader.cs
index e6cc7e5e40..c6e5e896a1 100644
--- a/src/Avalonia.Controls.DataGrid/DataGridColumnHeader.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGridColumnHeader.cs
@@ -13,6 +13,7 @@ using System.Diagnostics;
 using Avalonia.Utilities;
 using System;
 using Avalonia.Controls.Utils;
+using Avalonia.Controls.Mixins;
 
 namespace Avalonia.Controls
 {
@@ -68,6 +69,7 @@ namespace Avalonia.Controls
         static DataGridColumnHeader()
         {
             AreSeparatorsVisibleProperty.Changed.AddClassHandler<DataGridColumnHeader>((x, e) => x.OnAreSeparatorsVisibleChanged(e));
+            PressedMixin.Attach<DataGridColumnHeader>();
         }
 
         /// <summary>
@@ -149,8 +151,7 @@ namespace Avalonia.Controls
             }
         }
 
-        //TODO Implement
-        internal void ApplyState()
+        internal void UpdatePseudoClasses()
         {
             CurrentSortingState = null;
             if (OwningGrid != null
@@ -441,7 +442,7 @@ namespace Avalonia.Controls
 
             Point mousePosition = e.GetPosition(this);
             OnMouseEnter(mousePosition);
-            ApplyState();
+            UpdatePseudoClasses();
         }
 
         private void DataGridColumnHeader_PointerLeave(object sender, PointerEventArgs e)
@@ -452,7 +453,7 @@ namespace Avalonia.Controls
             }
 
             OnMouseLeave();
-            ApplyState();
+            UpdatePseudoClasses();
         }
 
         private void DataGridColumnHeader_PointerPressed(object sender, PointerPressedEventArgs e)
@@ -467,7 +468,7 @@ namespace Avalonia.Controls
             OnMouseLeftButtonDown(ref handled, e, mousePosition);
             e.Handled = handled;
 
-            ApplyState();
+            UpdatePseudoClasses();
         }
 
         private void DataGridColumnHeader_PointerReleased(object sender, PointerReleasedEventArgs e)
@@ -483,7 +484,7 @@ namespace Avalonia.Controls
             OnMouseLeftButtonUp(ref handled, e, mousePosition, mousePositionHeaders);
             e.Handled = handled;
 
-            ApplyState();
+            UpdatePseudoClasses();
         }
 
         private void DataGridColumnHeader_PointerMove(object sender, PointerEventArgs e)
diff --git a/src/Avalonia.Controls.DataGrid/DataGridDataConnection.cs b/src/Avalonia.Controls.DataGrid/DataGridDataConnection.cs
index e21ee3be37..19539bf032 100644
--- a/src/Avalonia.Controls.DataGrid/DataGridDataConnection.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGridDataConnection.cs
@@ -610,7 +610,7 @@ namespace Avalonia.Controls
             // refresh sort description
             foreach (DataGridColumn column in _owner.ColumnsItemsInternal)
             {
-                column.HeaderCell.ApplyState();
+                column.HeaderCell.UpdatePseudoClasses();
             }
         }
 
diff --git a/src/Avalonia.Controls.DataGrid/DataGridRow.cs b/src/Avalonia.Controls.DataGrid/DataGridRow.cs
index d5115c983a..aa0ac11b64 100644
--- a/src/Avalonia.Controls.DataGrid/DataGridRow.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGridRow.cs
@@ -624,17 +624,17 @@ namespace Avalonia.Controls
         {
             if (_headerElement != null && OwningGrid.AreRowHeadersVisible)
             {
-                _headerElement.ApplyOwnerStatus();
+                _headerElement.UpdatePseudoClasses();
             }
         }
 
-        //TODO Implement
         internal void UpdatePseudoClasses()
         {
-            PseudoClasses.Set(":selected", IsSelected);
-            PseudoClasses.Set(":editing", IsEditing);
             if (RootElement != null && OwningGrid != null && IsVisible)
             {
+                PseudoClasses.Set(":selected", IsSelected);
+                PseudoClasses.Set(":editing", IsEditing);
+                PseudoClasses.Set(":invalid", !IsValid);
                 ApplyHeaderStatus();
             } 
         }
diff --git a/src/Avalonia.Controls.DataGrid/DataGridRowGroupHeader.cs b/src/Avalonia.Controls.DataGrid/DataGridRowGroupHeader.cs
index 0790fcf5d5..e504fe73a8 100644
--- a/src/Avalonia.Controls.DataGrid/DataGridRowGroupHeader.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGridRowGroupHeader.cs
@@ -3,6 +3,7 @@
 // Please see http://go.microsoft.com/fwlink/?LinkID=131993 for details.
 // All other rights reserved.
 
+using Avalonia.Controls.Mixins;
 using Avalonia.Controls.Primitives;
 using Avalonia.Input;
 using Avalonia.Media;
@@ -96,6 +97,7 @@ namespace Avalonia.Controls
         static DataGridRowGroupHeader()
         {
             SublevelIndentProperty.Changed.AddClassHandler<DataGridRowGroupHeader>((x,e) => x.OnSublevelIndentChanged(e));
+            PressedMixin.Attach<DataGridRowGroupHeader>();
         }
 
         /// <summary>
@@ -205,14 +207,18 @@ namespace Avalonia.Controls
         {
             if (_headerElement != null && OwningGrid.AreRowHeadersVisible)
             {
-                _headerElement.ApplyOwnerStatus();
+                _headerElement.UpdatePseudoClasses();
             }
         }
 
-        //TODO Implement
-        internal void ApplyState(bool useTransitions)
+        internal void UpdatePseudoClasses()
         {
+            PseudoClasses.Set(":current", IsCurrent);
 
+            if (RowGroupInfo?.CollectionViewGroup != null)
+            {
+                PseudoClasses.Set(":expanded", RowGroupInfo.IsVisible && RowGroupInfo.CollectionViewGroup.ItemCount > 0);
+            }
         }
 
         protected override Size ArrangeOverride(Size finalSize)
@@ -344,7 +350,7 @@ namespace Avalonia.Controls
         {
             EnsureExpanderButtonIsChecked();
             EnsureHeaderVisibility();
-            ApplyState(useTransitions: false);
+            UpdatePseudoClasses();
             ApplyHeaderStatus();
         }
 
@@ -353,7 +359,7 @@ namespace Avalonia.Controls
             if (IsEnabled)
             {
                 IsMouseOver = true;
-                ApplyState(useTransitions: true);
+                UpdatePseudoClasses();
             }
 
             base.OnPointerEnter(e);
@@ -364,7 +370,7 @@ namespace Avalonia.Controls
             if (IsEnabled)
             {
                 IsMouseOver = false;
-                ApplyState(useTransitions: true);
+                UpdatePseudoClasses();
             }
 
             base.OnPointerLeave(e);
@@ -402,7 +408,7 @@ namespace Avalonia.Controls
 
                 EnsureExpanderButtonIsChecked();
 
-                ApplyState(true /*useTransitions*/);
+                UpdatePseudoClasses();
             }
         }
 
diff --git a/src/Avalonia.Controls.DataGrid/DataGridRowHeader.cs b/src/Avalonia.Controls.DataGrid/DataGridRowHeader.cs
index 324227d749..3b121879b1 100644
--- a/src/Avalonia.Controls.DataGrid/DataGridRowHeader.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGridRowHeader.cs
@@ -99,7 +99,7 @@ namespace Avalonia.Controls.Primitives
             _rootElement = e.NameScope.Find<Control>(DATAGRIDROWHEADER_elementRootName);
             if (_rootElement != null)
             {
-                ApplyOwnerStatus();
+                UpdatePseudoClasses();
             }
         } 
 
@@ -131,12 +131,27 @@ namespace Avalonia.Controls.Primitives
             return measuredSize;
         }
 
-        //TODO Implement
-        internal void ApplyOwnerStatus()
+        internal void UpdatePseudoClasses()
         {
             if (_rootElement != null && Owner != null && Owner.IsVisible)
             {
+                if (OwningRow != null)
+                {
+                    PseudoClasses.Set(":invalid", !OwningRow.IsValid);
+
+                    PseudoClasses.Set(":selected", OwningRow.IsSelected);
+
+                    PseudoClasses.Set(":editing", OwningRow.IsEditing);
 
+                    if (OwningGrid != null)
+                    {
+                        PseudoClasses.Set(":current", OwningRow.Slot == OwningGrid.CurrentSlot);
+                    }
+                }
+                else if (OwningRowGroupHeader != null && OwningGrid != null)
+                {
+                    PseudoClasses.Set(":current", OwningRowGroupHeader.RowGroupInfo.Slot == OwningGrid.CurrentSlot);
+                }
             }
         }
 
diff --git a/src/Avalonia.Controls.DataGrid/DataGridRows.cs b/src/Avalonia.Controls.DataGrid/DataGridRows.cs
index 924156f5f4..a69b8eafe1 100644
--- a/src/Avalonia.Controls.DataGrid/DataGridRows.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGridRows.cs
@@ -1912,7 +1912,7 @@ namespace Avalonia.Controls
             {
                 // Assume it's a RowGroupHeader
                 DataGridRowGroupHeader groupHeader = element as DataGridRowGroupHeader;
-                groupHeader.ApplyState(useTransitions: true);
+                groupHeader.UpdatePseudoClasses();
             }
         }
 

From 8fb31061b5e933a189c04b0b6b53a082945cc325 Mon Sep 17 00:00:00 2001
From: Maksym Katsydan <maxkatz6@outlook.com>
Date: Fri, 21 Aug 2020 00:35:32 -0400
Subject: [PATCH 3/8] Fluent DataGrid styles

---
 .../Themes/Fluent.xaml                        | 563 ++++++++++++++----
 1 file changed, 463 insertions(+), 100 deletions(-)

diff --git a/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml b/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
index a32989372c..3c49999099 100644
--- a/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
+++ b/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
@@ -1,13 +1,141 @@
-<Styles xmlns="https://github.com/avaloniaui">
-  <!--  TODO: Validation and Focus  -->
+<Styles xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+  <Styles.Resources>
+    <SolidColorBrush x:Key="DropLocationIndicatorBackground"
+                     Color="#3F4346" />
+    <SolidColorBrush x:Key="DisabledVisualElementBackground"
+                     Color="#8CFFFFFF" />
+    <SolidColorBrush x:Key="InvalidBrush"
+                     Color="#FFFF00" />
+    <SolidColorBrush x:Key="FillerGridLinesBrush"
+                     Color="Transparent" />
+    <StaticResource x:Key="ScrollBarsSeparatorBackground"
+                    ResourceKey="SystemControlPageBackgroundChromeLowBrush" />
+    <StaticResource x:Key="DataGridColumnHeaderForegroundBrush"
+                    ResourceKey="SystemControlForegroundBaseMediumBrush" />
+    <StaticResource x:Key="DataGridColumnHeaderBackgroundColor"
+                    ResourceKey="SystemAltHighColor" />
+    <SolidColorBrush x:Key="DataGridColumnHeaderBackgroundBrush"
+                     Color="{StaticResource DataGridColumnHeaderBackgroundColor}" />
+    <StaticResource x:Key="DataGridColumnHeaderHoveredBackgroundColor"
+                    ResourceKey="SystemListLowColor" />
+    <StaticResource x:Key="DataGridColumnHeaderPressedBackgroundColor"
+                    ResourceKey="SystemListMediumColor" />
+    <StaticResource x:Key="DataGridColumnHeaderDraggedBackgroundBrush"
+                    ResourceKey="SystemControlBackgroundChromeMediumLowBrush" />
+    <StaticResource x:Key="DataGridColumnHeaderPointerOverBrush"
+                    ResourceKey="SystemControlHighlightListLowBrush" />
+    <StaticResource x:Key="DataGridColumnHeaderPressedBrush"
+                    ResourceKey="SystemControlHighlightListMediumBrush" />
+
+    <SolidColorBrush x:Key="SystemControlGridLinesBaseMediumLowBrush"
+                     Color="{StaticResource SystemBaseMediumLowColor}"
+                     Opacity="0.4" />
+    <SolidColorBrush x:Key="SystemControlRowGroupHeaderBackgroundMediumBrush"
+                     Color="{StaticResource SystemChromeMediumColor}" />
+    <SolidColorBrush x:Key="DataGridCurrencyVisualPrimaryBrush"
+                     Color="Transparent" />
+
+    <StreamGeometry x:Key="SortIconAscendingPath">M1875 1011l-787 787v-1798h-128v1798l-787 -787l-90 90l941 941l941 -941z</StreamGeometry>
+    <StreamGeometry x:Key="SortIconDescendingPath">M1965 947l-941 -941l-941 941l90 90l787 -787v1798h128v-1798l787 787z</StreamGeometry>
+    <StreamGeometry x:Key="RowGroupHeaderIconClosedPath">M515 93l930 931l-930 931l90 90l1022 -1021l-1022 -1021z</StreamGeometry>
+    <StreamGeometry x:Key="RowGroupHeaderIconOpenedPath">M1939 1581l90 -90l-1005 -1005l-1005 1005l90 90l915 -915z</StreamGeometry>
+
+    <!--<x:String x:Key="ScrollBarsSeparatorExpandBeginTime">00:00:00.40</x:String>
+    <x:String x:Key="ScrollBarsSeparatorExpandDuration">00:00:00.1</x:String>
+    <x:String x:Key="ScrollBarsSeparatorContractBeginTime">00:00:02.00</x:String>
+    <x:String x:Key="ScrollBarsSeparatorContractDelay">00:00:02</x:String>
+    <x:String x:Key="ScrollBarsSeparatorContractDuration">00:00:00.1</x:String>
+    <x:String x:Key="ScrollBarsSeparatorContractFinalKeyframe">00:00:02.1</x:String>
+    <x:String x:Key="ScrollBarsSeparatorNoTouchDuration">00:00:00.5</x:String>-->
+
+    <x:Double x:Key="ListAccentLowOpacity">0.6</x:Double>
+    <x:Double x:Key="ListAccentMediumOpacity">0.8</x:Double>
+
+    <StaticResource x:Key="GridLinesBrush"
+                    ResourceKey="SystemControlGridLinesBaseMediumLowBrush" />
+
+    <StaticResource x:Key="DataGridDetailsPresenterBackgroundBrush"
+                    ResourceKey="SystemControlBackgroundChromeMediumLowBrush" />
+    <StaticResource x:Key="DataGridFillerColumnGridLinesBrush"
+                    ResourceKey="FillerGridLinesBrush" />
+    <StaticResource x:Key="DataGridRowSelectedBackgroundColor"
+                    ResourceKey="SystemAccentColor" />
+    <StaticResource x:Key="DataGridRowSelectedBackgroundOpacity"
+                    ResourceKey="ListAccentLowOpacity" />
+    <StaticResource x:Key="DataGridRowSelectedHoveredBackgroundColor"
+                    ResourceKey="SystemAccentColor" />
+    <StaticResource x:Key="DataGridRowSelectedHoveredBackgroundOpacity"
+                    ResourceKey="ListAccentMediumOpacity" />
+    <StaticResource x:Key="DataGridRowSelectedUnfocusedBackgroundColor"
+                    ResourceKey="SystemAccentColor" />
+    <StaticResource x:Key="DataGridRowSelectedUnfocusedBackgroundOpacity"
+                    ResourceKey="ListAccentLowOpacity" />
+    <StaticResource x:Key="DataGridRowSelectedHoveredUnfocusedBackgroundColor"
+                    ResourceKey="SystemAccentColor" />
+    <StaticResource x:Key="DataGridRowSelectedHoveredUnfocusedBackgroundOpacity"
+                    ResourceKey="ListAccentMediumOpacity" />
+    <StaticResource x:Key="DataGridRowHeaderForegroundBrush"
+                    ResourceKey="SystemControlForegroundBaseMediumBrush" />
+    <StaticResource x:Key="DataGridRowHeaderBackgroundBrush"
+                    ResourceKey="SystemControlBackgroundAltHighBrush" />
+    <StaticResource x:Key="DataGridRowGroupHeaderBackgroundBrush"
+                    ResourceKey="SystemControlBackgroundChromeMediumBrush" />
+    <StaticResource x:Key="DataGridRowGroupHeaderHoveredBackgroundBrush"
+                    ResourceKey="SystemControlBackgroundListLowBrush" />
+    <StaticResource x:Key="DataGridRowGroupHeaderPressedBackgroundBrush"
+                    ResourceKey="SystemControlBackgroundListMediumBrush" />
+    <StaticResource x:Key="DataGridRowGroupHeaderForegroundBrush"
+                    ResourceKey="SystemControlForegroundBaseHighBrush" />
+    <StaticResource x:Key="DataGridRowInvalidBrush"
+                    ResourceKey="InvalidBrush" />
+    <StaticResource x:Key="DataGridCellBackgroundBrush"
+                    ResourceKey="SystemControlTransparentBrush" />
+    <StaticResource x:Key="DataGridCellFocusVisualPrimaryBrush"
+                    ResourceKey="SystemControlFocusVisualPrimaryBrush" />
+    <StaticResource x:Key="DataGridCellFocusVisualSecondaryBrush"
+                    ResourceKey="SystemControlFocusVisualSecondaryBrush" />
+    <StaticResource x:Key="DataGridCellInvalidBrush"
+                    ResourceKey="InvalidBrush" />
+  </Styles.Resources>
+
   <Style Selector="DataGridCell">
-    <Setter Property="Background" Value="Transparent" />
+    <Setter Property="Background" Value="{DynamicResource DataGridCellBackgroundBrush}" />
     <Setter Property="HorizontalContentAlignment" Value="Stretch" />
     <Setter Property="VerticalContentAlignment" Value="Stretch" />
+    <Setter Property="FontSize" Value="15" />
+    <Setter Property="MinHeight" Value="32" />
+    <Setter Property="Focusable" Value="False" />
     <Setter Property="Template">
       <ControlTemplate>
-        <Grid ColumnDefinitions="*,Auto"
+        <Grid x:Name="PART_CellRoot"
+              ColumnDefinitions="*,Auto"
               Background="{TemplateBinding Background}">
+
+          <Rectangle x:Name="CurrencyVisual"
+                     HorizontalAlignment="Stretch"
+                     VerticalAlignment="Stretch"
+                     Fill="Transparent"
+                     IsHitTestVisible="False"
+                     Stroke="{DynamicResource DataGridCurrencyVisualPrimaryBrush}"
+                     StrokeThickness="1" />
+          <Grid x:Name="FocusVisual"
+                IsHitTestVisible="False">
+            <Rectangle HorizontalAlignment="Stretch"
+                       VerticalAlignment="Stretch"
+                       Fill="Transparent"
+                       IsHitTestVisible="False"
+                       Stroke="{DynamicResource DataGridCellFocusVisualPrimaryBrush}"
+                       StrokeThickness="2" />
+            <Rectangle Margin="2"
+                       HorizontalAlignment="Stretch"
+                       VerticalAlignment="Stretch"
+                       Fill="Transparent"
+                       IsHitTestVisible="False"
+                       Stroke="{DynamicResource DataGridCellFocusVisualSecondaryBrush}"
+                       StrokeThickness="1" />
+          </Grid>
+
           <ContentPresenter ContentTemplate="{TemplateBinding ContentTemplate}"
                             Content="{TemplateBinding Content}"
                             Margin="{TemplateBinding Padding}"
@@ -15,44 +143,76 @@
                             HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
                             VerticalAlignment="{TemplateBinding VerticalContentAlignment}" />
 
+          <Rectangle x:Name="InvalidVisualElement"
+                     HorizontalAlignment="Stretch"
+                     VerticalAlignment="Stretch"
+                     IsHitTestVisible="False"
+                     Stroke="{DynamicResource DataGridCellInvalidBrush}"
+                     StrokeThickness="1" />
+
           <Rectangle Name="PART_RightGridLine"
                      Grid.Column="1"
                      VerticalAlignment="Stretch"
-                     Width="1" />
+                     Width="1"
+                     Fill="{DynamicResource DataGridFillerColumnGridLinesBrush}" />
         </Grid>
       </ControlTemplate>
     </Setter>
   </Style>
 
+  <Style Selector="DataGridCell /template/ Rectangle#CurrencyVisual">
+    <Setter Property="IsVisible" Value="False" />
+  </Style>
+  <Style Selector="DataGridCell /template/ Grid#FocusVisual">
+    <Setter Property="IsVisible" Value="False" />
+  </Style>
+  <Style Selector="DataGridCell:current /template/ Rectangle#CurrencyVisual">
+    <Setter Property="IsVisible" Value="True" />
+  </Style>
+  <Style Selector="DataGrid:focus DataGridCell:current /template/ Grid#FocusVisual">
+    <Setter Property="IsVisible" Value="True" />
+  </Style>
+  <Style Selector="DataGridCell /template/ Rectangle#InvalidVisualElement">
+    <Setter Property="IsVisible" Value="False" />
+  </Style>
+  <Style Selector="DataGridCell:invalid /template/ Rectangle#InvalidVisualElement">
+    <Setter Property="IsVisible" Value="True" />
+  </Style>
+
   <Style Selector="DataGridColumnHeader">
-    <Setter Property="Foreground" Value="{DynamicResource ThemeForegroundBrush}" />
-    <Setter Property="HorizontalContentAlignment" Value="Left" />
+    <Setter Property="Foreground" Value="{DynamicResource DataGridColumnHeaderForegroundBrush}" />
+    <Setter Property="Background" Value="{DynamicResource DataGridColumnHeaderBackgroundBrush}" />
+    <Setter Property="HorizontalContentAlignment" Value="Stretch" />
     <Setter Property="VerticalContentAlignment" Value="Center" />
-    <Setter Property="SeparatorBrush" Value="{DynamicResource ThemeControlLowColor}" />
-    <Setter Property="Padding" Value="4" />
-    <Setter Property="Background" Value="{DynamicResource ThemeControlMidBrush}" />
-
+    <Setter Property="Focusable" Value="False" />
+    <Setter Property="SeparatorBrush" Value="{DynamicResource GridLinesBrush}" />
+    <Setter Property="Padding" Value="12,0,0,0" />
+    <Setter Property="FontSize" Value="12" />
+    <Setter Property="MinHeight" Value="32" />
     <Setter Property="Template">
       <ControlTemplate>
-        <Grid ColumnDefinitions="*,Auto"
+        <Grid Name="PART_ColumnHeaderRoot"
+              ColumnDefinitions="*,Auto"
               Background="{TemplateBinding Background}">
 
-          <Grid ColumnDefinitions="*,Auto"
-                HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
+          <Grid HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
                 VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
                 Margin="{TemplateBinding Padding}">
+            <Grid.ColumnDefinitions>
+              <ColumnDefinition Width="*" />
+              <ColumnDefinition MinWidth="32"
+                                Width="Auto" />
+            </Grid.ColumnDefinitions>
+
             <ContentPresenter Content="{TemplateBinding Content}" />
 
             <Path Name="SortIcon"
                   Grid.Column="1"
                   Fill="{TemplateBinding Foreground}"
-                  HorizontalAlignment="Left"
+                  HorizontalAlignment="Center"
                   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 " />
-
+                  Height="12" />
           </Grid>
 
           <Rectangle Name="VerticalSeparator"
@@ -62,40 +222,66 @@
                      Fill="{TemplateBinding SeparatorBrush}"
                      IsVisible="{TemplateBinding AreSeparatorsVisible}" />
 
+          <Grid x:Name="FocusVisual"
+                IsHitTestVisible="False">
+            <Rectangle x:Name="FocusVisualPrimary"
+                       HorizontalAlignment="Stretch"
+                       VerticalAlignment="Stretch"
+                       Fill="Transparent"
+                       IsHitTestVisible="False"
+                       Stroke="{DynamicResource DataGridCellFocusVisualPrimaryBrush}"
+                       StrokeThickness="2" />
+            <Rectangle x:Name="FocusVisualSecondary"
+                       Margin="2"
+                       HorizontalAlignment="Stretch"
+                       VerticalAlignment="Stretch"
+                       Fill="Transparent"
+                       IsHitTestVisible="False"
+                       Stroke="{DynamicResource DataGridCellFocusVisualSecondaryBrush}"
+                       StrokeThickness="1" />
+          </Grid>
         </Grid>
       </ControlTemplate>
     </Setter>
   </Style>
 
+  <Style Selector="DataGridColumnHeader /template/ Grid#FocusVisual">
+    <Setter Property="IsVisible" Value="False" />
+  </Style>
+  <Style Selector="DataGridColumnHeader:focus-visible /template/ Grid#FocusVisual">
+    <Setter Property="IsVisible" Value="True" />
+  </Style>
+
+  <Style Selector="DataGridColumnHeader /template/ Grid#PART_ColumnHeaderRoot">
+    <Setter Property="Background" Value="{DynamicResource DataGridColumnHeaderBackgroundColor}" />
+  </Style>
+  <Style Selector="DataGridColumnHeader:pointerover /template/ Grid#PART_ColumnHeaderRoot">
+    <Setter Property="Background" Value="{DynamicResource DataGridColumnHeaderHoveredBackgroundColor}" />
+  </Style>
+  <Style Selector="DataGridColumnHeader:pressed /template/ Grid#PART_ColumnHeaderRoot">
+    <Setter Property="Background" Value="{DynamicResource DataGridColumnHeaderPressedBackgroundColor}" />
+  </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" />
+    <Setter Property="Data" Value="{StaticResource SortIconAscendingPath}" />
   </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>
+    <Setter Property="Data" Value="{StaticResource SortIconDescendingPath}" />
   </Style>
 
   <Style Selector="DataGridRow">
+    <Setter Property="Focusable" Value="False" />
     <Setter Property="Template">
       <ControlTemplate>
         <DataGridFrozenGrid Name="PART_Root"
@@ -105,19 +291,23 @@
           <Rectangle Name="BackgroundRectangle"
                      Grid.RowSpan="2"
                      Grid.ColumnSpan="2" />
+          <Rectangle x:Name="InvalidVisualElement"
+                     Grid.ColumnSpan="2"
+                     Fill="{DynamicResource DataGridRowInvalidBrush}" />
 
-          <DataGridRowHeader Grid.RowSpan="3"
-                             Name="PART_RowHeader"
+          <DataGridRowHeader Name="PART_RowHeader"
+                             Grid.RowSpan="3"
                              DataGridFrozenGrid.IsFrozen="True" />
-          <DataGridCellsPresenter Grid.Column="1"
-                                  Name="PART_CellsPresenter"
+          <DataGridCellsPresenter Name="PART_CellsPresenter"
+                                  Grid.Column="1"
                                   DataGridFrozenGrid.IsFrozen="True" />
-          <DataGridDetailsPresenter Grid.Row="1"
+          <DataGridDetailsPresenter Name="PART_DetailsPresenter"
+                                    Grid.Row="1"
                                     Grid.Column="1"
-                                    Name="PART_DetailsPresenter" />
-          <Rectangle Grid.Row="2"
+                                    Background="{DynamicResource DataGridDetailsPresenterBackgroundBrush}" />
+          <Rectangle Name="PART_BottomGridLine"
+                     Grid.Row="2"
                      Grid.Column="1"
-                     Name="PART_BottomGridLine"
                      HorizontalAlignment="Stretch"
                      Height="1" />
 
@@ -126,71 +316,188 @@
     </Setter>
   </Style>
 
-  <Style Selector="DataGridRow /template/ Rectangle#BackgroundRectangle">
-    <Setter Property="IsVisible" Value="False" />
-    <Setter Property="Fill" Value="{DynamicResource HighlightBrush}" />
+  <Style Selector="DataGridRow /template/ Rectangle#InvalidVisualElement">
+    <Setter Property="Opacity" Value="0" />
+  </Style>
+  <Style Selector="DataGridRow:invalid /template/ Rectangle#InvalidVisualElement">
+    <Setter Property="Opacity" Value="0.4" />
+  </Style>
+  <Style Selector="DataGridRow:invalid /template/ Rectangle#BackgroundRectangle">
+    <Setter Property="Opacity" Value="0" />
   </Style>
 
+  <Style Selector="DataGridRow /template/ Rectangle#BackgroundRectangle">
+    <Setter Property="Fill" Value="{DynamicResource SystemControlTransparentBrush}" />
+  </Style>
   <Style Selector="DataGridRow:pointerover /template/ Rectangle#BackgroundRectangle">
-    <Setter Property="IsVisible" Value="True" />
-    <Setter Property="Opacity" Value="0.5" />
+    <Setter Property="Fill" Value="{DynamicResource SystemListLowColor}" />
   </Style>
-
   <Style Selector="DataGridRow:selected /template/ Rectangle#BackgroundRectangle">
-    <Setter Property="IsVisible" Value="True" />
-    <Setter Property="Opacity" Value="1" />
+    <Setter Property="Fill" Value="{DynamicResource DataGridRowSelectedUnfocusedBackgroundColor}" />
+    <Setter Property="Opacity" Value="{DynamicResource DataGridRowSelectedUnfocusedBackgroundOpacity}" />
   </Style>
-
-  <Style Selector="DataGridRow:selected">
-    <Setter Property="Foreground" Value="{DynamicResource HighlightForegroundBrush}" />
+  <Style Selector="DataGridRow:selected:pointerover /template/ Rectangle#BackgroundRectangle">
+    <Setter Property="Fill" Value="{DynamicResource DataGridRowSelectedHoveredUnfocusedBackgroundColor}" />
+    <Setter Property="Opacity" Value="{DynamicResource DataGridRowSelectedHoveredUnfocusedBackgroundOpacity}" />
+  </Style>
+  <Style Selector="DataGridRow:selected:focus /template/ Rectangle#BackgroundRectangle">
+    <Setter Property="Fill" Value="{DynamicResource DataGridRowSelectedBackgroundColor}" />
+    <Setter Property="Opacity" Value="{DynamicResource DataGridRowSelectedBackgroundOpacity}" />
+  </Style>
+  <Style Selector="DataGridRow:selected:pointerover:focus /template/ Rectangle#BackgroundRectangle">
+    <Setter Property="Fill" Value="{DynamicResource DataGridRowSelectedHoveredBackgroundColor}" />
+    <Setter Property="Opacity" Value="{DynamicResource DataGridRowSelectedHoveredBackgroundOpacity}" />
   </Style>
 
   <Style Selector="DataGridRowHeader">
+    <Setter Property="Background" Value="{DynamicResource DataGridRowHeaderBackgroundBrush}" />
+    <Setter Property="Focusable" Value="False" />
+    <Setter Property="SeparatorBrush" Value="{DynamicResource GridLinesBrush}" />
+    <Setter Property="AreSeparatorsVisible" Value="False" />
     <Setter Property="Template">
       <ControlTemplate>
-        <Grid RowDefinitions="*,*,Auto"
-              ColumnDefinitions="Auto,*" />
+        <Grid x:Name="PART_RowHeaderRoot"
+              RowDefinitions="*,*,Auto"
+              ColumnDefinitions="Auto,*">
+          <Border Grid.RowSpan="3"
+                  Grid.ColumnSpan="2"
+                  BorderBrush="{TemplateBinding SeparatorBrush}"
+                  BorderThickness="0,0,1,0">
+            <Grid Background="{TemplateBinding Background}">
+              <Rectangle x:Name="RowInvalidVisualElement"
+                         Fill="{DynamicResource DataGridRowInvalidBrush}"
+                         Stretch="Fill" />
+              <Rectangle x:Name="BackgroundRectangle"
+                         Stretch="Fill" />
+            </Grid>
+          </Border>
+          <Rectangle x:Name="HorizontalSeparator"
+                     Grid.Row="2"
+                     Grid.ColumnSpan="2"
+                     Height="1"
+                     Margin="1,0,1,0"
+                     HorizontalAlignment="Stretch"
+                     Fill="{TemplateBinding SeparatorBrush}"
+                     IsVisible="{TemplateBinding AreSeparatorsVisible}" />
+
+          <ContentPresenter Grid.RowSpan="2"
+                            Grid.Column="1"
+                            HorizontalAlignment="Center"
+                            VerticalAlignment="Center"
+                            Content="{TemplateBinding Content}" />
+        </Grid>
       </ControlTemplate>
     </Setter>
   </Style>
 
+  <Style Selector="DataGridRowHeader /template/ Rectangle#RowInvalidVisualElement">
+    <Setter Property="Opacity" Value="0" />
+  </Style>
+  <Style Selector="DataGridRowHeader:invalid /template/ Rectangle#RowInvalidVisualElement">
+    <Setter Property="Opacity" Value="0.4" />
+  </Style>
+  <Style Selector="DataGridRowHeader:invalid /template/ Rectangle#BackgroundRectangle">
+    <Setter Property="Opacity" Value="0" />
+  </Style>
+
+  <Style Selector="DataGridRowHeader /template/ Rectangle#BackgroundRectangle">
+    <Setter Property="Fill" Value="{DynamicResource SystemControlTransparentBrush}" />
+  </Style>
+  <Style Selector="DataGridRowHeader:pointerover /template/ Rectangle#BackgroundRectangle">
+    <Setter Property="Fill" Value="{DynamicResource SystemListLowColor}" />
+  </Style>
+  <Style Selector="DataGridRowHeader:selected /template/ Rectangle#BackgroundRectangle">
+    <Setter Property="Fill" Value="{DynamicResource DataGridRowSelectedUnfocusedBackgroundColor}" />
+    <Setter Property="Opacity" Value="{DynamicResource DataGridRowSelectedUnfocusedBackgroundOpacity}" />
+  </Style>
+  <Style Selector="DataGridRowHeader:selected:pointerover /template/ Rectangle#BackgroundRectangle">
+    <Setter Property="Fill" Value="{DynamicResource DataGridRowSelectedHoveredUnfocusedBackgroundColor}" />
+    <Setter Property="Opacity" Value="{DynamicResource DataGridRowSelectedHoveredUnfocusedBackgroundOpacity}" />
+  </Style>
+  <Style Selector="DataGridRowHeader:selected:focus /template/ Rectangle#BackgroundRectangle">
+    <Setter Property="Fill" Value="{DynamicResource DataGridRowSelectedBackgroundColor}" />
+    <Setter Property="Opacity" Value="{DynamicResource DataGridRowSelectedBackgroundOpacity}" />
+  </Style>
+  <Style Selector="DataGridRowHeader:selected:pointerover:focus /template/ Rectangle#BackgroundRectangle">
+    <Setter Property="Fill" Value="{DynamicResource DataGridRowSelectedHoveredBackgroundColor}" />
+    <Setter Property="Opacity" Value="{DynamicResource DataGridRowSelectedHoveredBackgroundOpacity}" />
+  </Style>
+
   <Style Selector="DataGridRowGroupHeader">
-    <Setter Property="Background" Value="{DynamicResource ThemeControlMidHighBrush}" />
-    <Setter Property="Height" Value="20" />
+    <Setter Property="Focusable" Value="False" />
+    <Setter Property="Foreground" Value="{DynamicResource DataGridRowGroupHeaderForegroundBrush}" />
+    <Setter Property="Background" Value="{DynamicResource DataGridRowGroupHeaderBackgroundBrush}" />
+    <Setter Property="FontSize" Value="15" />
+    <Setter Property="MinHeight" Value="32" />
     <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" />
+                            MinHeight="{TemplateBinding MinHeight}"
+                            ColumnDefinitions="Auto,Auto,Auto,Auto,*"
+                            RowDefinitions="*,Auto">
+
+          <Rectangle Name="IndentSpacer"
+                     Grid.Column="1" />
+          <ToggleButton Name="ExpanderButton"
+                        Grid.Column="2"
+                        Width="12"
+                        Height="12"
+                        Margin="12,0,0,0"
+                        Background="{TemplateBinding Background}"
+                        Foreground="{TemplateBinding Foreground}"
+                        Focusable="False" />
 
           <StackPanel Grid.Column="3"
-                      Grid.Row="1"
                       Orientation="Horizontal"
                       VerticalAlignment="Center"
-                      Margin="0,1,0,1">
+                      Margin="12,0,0,0">
             <TextBlock Name="PropertyNameElement"
                        Margin="4,0,0,0"
-                       IsVisible="{TemplateBinding IsPropertyNameVisible}" />
+                       IsVisible="{TemplateBinding IsPropertyNameVisible}"
+                       Foreground="{TemplateBinding Foreground}" />
             <TextBlock Margin="4,0,0,0"
-                       Text="{Binding Key}" />
+                       Text="{Binding Key}"
+                       Foreground="{TemplateBinding Foreground}" />
             <TextBlock Name="ItemCountElement"
                        Margin="4,0,0,0"
-                       IsVisible="{TemplateBinding IsItemCountVisible}" />
+                       IsVisible="{TemplateBinding IsItemCountVisible}"
+                       Foreground="{TemplateBinding Foreground}" />
           </StackPanel>
 
+          <Rectangle x:Name="CurrencyVisual"
+                     Grid.ColumnSpan="5"
+                     HorizontalAlignment="Stretch"
+                     VerticalAlignment="Stretch"
+                     Fill="Transparent"
+                     IsHitTestVisible="False"
+                     Stroke="{DynamicResource DataGridCurrencyVisualPrimaryBrush}"
+                     StrokeThickness="1" />
+          <Grid x:Name="FocusVisual"
+                Grid.ColumnSpan="5"
+                IsHitTestVisible="False">
+            <Rectangle HorizontalAlignment="Stretch"
+                       VerticalAlignment="Stretch"
+                       Fill="Transparent"
+                       IsHitTestVisible="False"
+                       Stroke="{DynamicResource DataGridCellFocusVisualPrimaryBrush}"
+                       StrokeThickness="2" />
+            <Rectangle Margin="2"
+                       HorizontalAlignment="Stretch"
+                       VerticalAlignment="Stretch"
+                       Fill="Transparent"
+                       IsHitTestVisible="False"
+                       Stroke="{DynamicResource DataGridCellFocusVisualSecondaryBrush}"
+                       StrokeThickness="1" />
+          </Grid>
+
           <DataGridRowHeader Name="RowHeader"
-                             Grid.RowSpan="3"
+                             Grid.RowSpan="2"
                              DataGridFrozenGrid.IsFrozen="True" />
 
+          <Rectangle x:Name="BottomGridLine"
+                     Grid.Row="1"
+                     Grid.ColumnSpan="5"
+                     Height="1" />
         </DataGridFrozenGrid>
       </ControlTemplate>
     </Setter>
@@ -200,42 +507,66 @@
     <Setter Property="Template">
       <ControlTemplate>
         <Border Grid.Column="0"
-                Width="20"
-                Height="20"
+                Width="12"
+                Height="12"
                 Background="Transparent"
                 HorizontalAlignment="Center"
                 VerticalAlignment="Center">
           <Path Fill="{TemplateBinding Foreground}"
-                HorizontalAlignment="Center"
+                HorizontalAlignment="Right"
                 VerticalAlignment="Center"
-                Data="M 0 2 L 4 6 L 0 10 Z" />
+                Stretch="Uniform" />
         </Border>
       </ControlTemplate>
     </Setter>
   </Style>
 
+  <Style Selector="DataGridRowGroupHeader /template/ ToggleButton#ExpanderButton /template/ Path">
+    <Setter Property="Data" Value="{StaticResource RowGroupHeaderIconOpenedPath}" />
+    <Setter Property="Stretch" Value="Uniform" />
+  </Style>
+
   <Style Selector="DataGridRowGroupHeader /template/ ToggleButton#ExpanderButton:checked /template/ Path">
-    <Setter Property="RenderTransform">
-      <RotateTransform Angle="90" />
-    </Setter>
+    <Setter Property="Data" Value="{StaticResource RowGroupHeaderIconClosedPath}" />
+    <Setter Property="Stretch" Value="UniformToFill" />
+  </Style>
+
+  <Style Selector="DataGridRowGroupHeader /template/ DataGridFrozenGrid#Root">
+    <Setter Property="Background" Value="{Binding $parent[DataGridRowGroupHeader].Background}" />
+  </Style>
+  <Style Selector="DataGridRowGroupHeader:pointerover /template/ DataGridFrozenGrid#Root">
+    <Setter Property="Background" Value="{DynamicResource DataGridRowGroupHeaderHoveredBackgroundBrush}" />
+  </Style>
+  <Style Selector="DataGridRowGroupHeader:pressed /template/ DataGridFrozenGrid#Root">
+    <Setter Property="Background" Value="{DynamicResource DataGridRowGroupHeaderPressedBackgroundBrush}" />
+  </Style>
+
+  <Style Selector="DataGridRowGroupHeader /template/ Rectangle#CurrencyVisual">
+    <Setter Property="IsVisible" Value="False" />
+  </Style>
+  <Style Selector="DataGridRowGroupHeader /template/ Grid#FocusVisual">
+    <Setter Property="IsVisible" Value="False" />
+  </Style>
+  <Style Selector="DataGridRowGroupHeader:current /template/ Rectangle#CurrencyVisual">
+    <Setter Property="IsVisible" Value="True" />
+  </Style>
+  <Style Selector="DataGrid:focus DataGridRowGroupHeader:current /template/ Grid#FocusVisual">
+    <Setter Property="IsVisible" Value="True" />
   </Style>
 
   <Style Selector="DataGrid">
-    <Setter Property="RowBackground" Value="{DynamicResource ThemeAccentBrush4}" />
-    <Setter Property="AlternatingRowBackground" Value="#00FFFFFF" />
-    <Setter Property="Background" Value="{DynamicResource ThemeBackgroundBrush}" />
+    <Setter Property="RowBackground" Value="Transparent" />
+    <Setter Property="AlternatingRowBackground" Value="Transparent" />
     <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="GridLinesVisibility" Value="None" />
+    <Setter Property="HorizontalGridLinesBrush" Value="{DynamicResource GridLinesBrush}" />
+    <Setter Property="VerticalGridLinesBrush" Value="{DynamicResource GridLinesBrush}" />
     <Setter Property="DropLocationIndicatorTemplate">
       <Template>
-        <Rectangle Fill="{DynamicResource ThemeBorderHighColor}"
+        <Rectangle Fill="{DynamicResource DropLocationIndicatorBackground}"
                    Width="2" />
       </Template>
     </Setter>
@@ -246,36 +577,59 @@
                 BorderBrush="{TemplateBinding BorderBrush}">
           <Grid RowDefinitions="Auto,*,Auto,Auto"
                 ColumnDefinitions="Auto,*,Auto">
+            <Grid.Resources>
+              <ControlTemplate x:Key="TopLeftHeaderTemplate"
+                               TargetType="DataGridColumnHeader">
+                <Grid x:Name="TopLeftHeaderRoot"
+                      RowDefinitions="*,*,Auto">
+                  <Border Grid.RowSpan="2"
+                          BorderThickness="0,0,1,0"
+                          BorderBrush="{DynamicResource GridLinesBrush}" />
+                  <Rectangle Grid.RowSpan="2"
+                             VerticalAlignment="Bottom"
+                             StrokeThickness="1"
+                             Height="1"
+                             Fill="{DynamicResource GridLinesBrush}" />
+                </Grid>
+              </ControlTemplate>
+              <ControlTemplate x:Key="TopRightHeaderTemplate"
+                               TargetType="DataGridColumnHeader">
+                <Grid x:Name="RootElement" />
+              </ControlTemplate>
+            </Grid.Resources>
 
             <DataGridColumnHeader Name="PART_TopLeftCornerHeader"
-                                  Width="22" />
+                                  Template="{StaticResource TopLeftHeaderTemplate}" />
             <DataGridColumnHeadersPresenter Name="PART_ColumnHeadersPresenter"
-                                            Grid.Column="1" />
-            <DataGridColumnHeader Name="PART_TopRightCornerHeader"
-                                  Grid.Column="2" />
+                                            Grid.Column="1"
+                                            Grid.ColumnSpan="2" />
+            <!--<DataGridColumnHeader Name="PART_TopRightCornerHeader"
+                                  Grid.Column="2"
+                                  Template="{StaticResource TopRightHeaderTemplate}" />-->
             <Rectangle Name="PART_ColumnHeadersAndRowsSeparator"
                        Grid.ColumnSpan="3"
                        VerticalAlignment="Bottom"
                        StrokeThickness="1"
                        Height="1"
-                       Fill="{DynamicResource ThemeControlMidHighBrush}" />
+                       Fill="{DynamicResource GridLinesBrush}" />
 
             <DataGridRowsPresenter Name="PART_RowsPresenter"
-                                   Grid.ColumnSpan="2"
-                                   Grid.Row="1" />
+                                   Grid.Row="1"
+                                   Grid.RowSpan="2"
+                                   Grid.ColumnSpan="3" />
             <Rectangle Name="BottomRightCorner"
-                       Fill="{DynamicResource ThemeControlMidHighBrush}"
+                       Fill="{DynamicResource ScrollBarsSeparatorBackground}"
                        Grid.Column="2"
                        Grid.Row="2" />
-            <Rectangle Name="BottomLeftCorner"
-                       Fill="{DynamicResource ThemeControlMidHighBrush}"
+            <!--<Rectangle Name="BottomLeftCorner"
+                       Fill="{DynamicResource ScrollBarsSeparatorBackground}"
                        Grid.Row="2"
-                       Grid.ColumnSpan="2" />
+                       Grid.ColumnSpan="2" />-->
             <ScrollBar Name="PART_VerticalScrollbar"
                        Orientation="Vertical"
                        Grid.Column="2"
                        Grid.Row="1"
-                       Width="{DynamicResource ScrollBarThickness}" />
+                       Width="{DynamicResource ScrollBarSize}" />
 
             <Grid Grid.Column="1"
                   Grid.Row="2"
@@ -284,8 +638,17 @@
               <ScrollBar Name="PART_HorizontalScrollbar"
                          Grid.Column="1"
                          Orientation="Horizontal"
-                         Height="{DynamicResource ScrollBarThickness}" />
+                         Height="{DynamicResource ScrollBarSize}" />
             </Grid>
+            <Border x:Name="PART_DisabledVisualElement"
+                    Grid.ColumnSpan="3"
+                    Grid.RowSpan="4"
+                    IsHitTestVisible="False"
+                    HorizontalAlignment="Stretch"
+                    VerticalAlignment="Stretch"
+                    CornerRadius="2"
+                    Background="{DynamicResource DisabledVisualElementBackground}"
+                    IsVisible="{Binding !$parent[DataGrid].IsEnabled}" />
           </Grid>
         </Border>
       </ControlTemplate>

From 7baca60f748b1d402998efb9f5ab3dbea7b34a68 Mon Sep 17 00:00:00 2001
From: Maksym Katsydan <maxkatz6@outlook.com>
Date: Mon, 24 Aug 2020 00:35:58 -0400
Subject: [PATCH 4/8] DataGrid: do not hardcode padding

---
 src/Avalonia.Controls.DataGrid/DataGridTextColumn.cs | 4 +++-
 src/Avalonia.Controls.DataGrid/Themes/Default.xaml   | 8 +++++++-
 src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml    | 2 ++
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/Avalonia.Controls.DataGrid/DataGridTextColumn.cs b/src/Avalonia.Controls.DataGrid/DataGridTextColumn.cs
index 589cdc253c..d31204b9e6 100644
--- a/src/Avalonia.Controls.DataGrid/DataGridTextColumn.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGridTextColumn.cs
@@ -9,6 +9,7 @@ using Avalonia.Media;
 using System;
 using System.ComponentModel;
 using Avalonia.Layout;
+using Avalonia.Markup.Xaml.MarkupExtensions;
 
 namespace Avalonia.Controls
 {
@@ -17,6 +18,7 @@ namespace Avalonia.Controls
     /// </summary>
     public class DataGridTextColumn : DataGridBoundColumn
     {
+        private const string DATAGRID_TextColumnCellTextBlockMarginKey = "DataGridTextColumnCellTextBlockMargin";
 
         private double? _fontSize;
         private FontStyle? _fontStyle;
@@ -186,7 +188,7 @@ namespace Avalonia.Controls
         {
             TextBlock textBlockElement = new TextBlock
             {
-                Margin = new Thickness(4),
+                [!Layoutable.MarginProperty] = new DynamicResourceExtension(DATAGRID_TextColumnCellTextBlockMarginKey),
                 VerticalAlignment = VerticalAlignment.Center
             };
 
diff --git a/src/Avalonia.Controls.DataGrid/Themes/Default.xaml b/src/Avalonia.Controls.DataGrid/Themes/Default.xaml
index 1d4d88825f..f7ac0f24e4 100644
--- a/src/Avalonia.Controls.DataGrid/Themes/Default.xaml
+++ b/src/Avalonia.Controls.DataGrid/Themes/Default.xaml
@@ -1,5 +1,11 @@
-<Styles xmlns="https://github.com/avaloniaui">
+<Styles xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <!--TODO: Validation and Focus-->
+
+  <Styles.Resources>
+    <Thickness x:Key="DataGridTextColumnCellTextBlockMargin">4</Thickness>
+  </Styles.Resources>
+  
   <Style Selector="DataGridCell">
     <Setter Property="Background" Value="Transparent"/>
     <Setter Property="HorizontalContentAlignment" Value="Stretch" />
diff --git a/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml b/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
index 3c49999099..85c1af10ef 100644
--- a/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
+++ b/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
@@ -1,6 +1,8 @@
 <Styles xmlns="https://github.com/avaloniaui"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <Styles.Resources>
+    <Thickness x:Key="DataGridTextColumnCellTextBlockMargin">12,0,12,0</Thickness>
+    
     <SolidColorBrush x:Key="DropLocationIndicatorBackground"
                      Color="#3F4346" />
     <SolidColorBrush x:Key="DisabledVisualElementBackground"

From 16ce3e78d0728577bd381e3a7ae3ecc30c3b61b3 Mon Sep 17 00:00:00 2001
From: Maksym Katsydan <maxkatz6@outlook.com>
Date: Mon, 24 Aug 2020 01:47:30 -0400
Subject: [PATCH 5/8] DataGrid: fix row headers (only fluent)

---
 .../ControlCatalog/Pages/DataGridPage.xaml    |  2 +-
 .../ControlCatalog/Pages/DataGridPage.xaml.cs |  7 ++++++-
 .../DataGridCell.cs                           |  4 ++--
 .../DataGridRowGroupHeader.cs                 |  2 +-
 .../Themes/Fluent.xaml                        | 20 +++++++++----------
 5 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/samples/ControlCatalog/Pages/DataGridPage.xaml b/samples/ControlCatalog/Pages/DataGridPage.xaml
index d1742c12b7..7b86bba6a9 100644
--- a/samples/ControlCatalog/Pages/DataGridPage.xaml
+++ b/samples/ControlCatalog/Pages/DataGridPage.xaml
@@ -18,7 +18,7 @@
     </StackPanel>
     <TabControl Grid.Row="1">
       <TabItem Header="DataGrid">
-        <DataGrid Name="dataGrid1" Margin="12" CanUserResizeColumns="True" CanUserReorderColumns="True">
+        <DataGrid Name="dataGrid1" Margin="12" CanUserResizeColumns="True" CanUserReorderColumns="True" CanUserSortColumns="True" HeadersVisibility="All">
           <DataGrid.Columns>
             <DataGridTextColumn Header="Country" Binding="{Binding Name}" Width="6*" />
             <DataGridTextColumn Header="Region" Binding="{Binding Region}" Width="4*" />
diff --git a/samples/ControlCatalog/Pages/DataGridPage.xaml.cs b/samples/ControlCatalog/Pages/DataGridPage.xaml.cs
index b8f63cf3e3..fea18aa5da 100644
--- a/samples/ControlCatalog/Pages/DataGridPage.xaml.cs
+++ b/samples/ControlCatalog/Pages/DataGridPage.xaml.cs
@@ -13,7 +13,7 @@ namespace ControlCatalog.Pages
             this.InitializeComponent();
             var dg1 = this.FindControl<DataGrid>("dataGrid1");
             dg1.IsReadOnly = true;
-
+            dg1.LoadingRow += Dg1_LoadingRow;
             var collectionView1 = new DataGridCollectionView(Countries.All);
             //collectionView.GroupDescriptions.Add(new PathGroupDescription("Region"));
 
@@ -44,6 +44,11 @@ namespace ControlCatalog.Pages
             addButton.Click += (a, b) => collectionView3.AddNew();
         }
 
+        private void Dg1_LoadingRow(object sender, DataGridRowEventArgs e)
+        {
+            e.Row.Header = e.Row.GetIndex() + 1;
+        }
+
         private void InitializeComponent()
         {
             AvaloniaXamlLoader.Load(this);
diff --git a/src/Avalonia.Controls.DataGrid/DataGridCell.cs b/src/Avalonia.Controls.DataGrid/DataGridCell.cs
index 99efc5743d..e5fbfa1a81 100644
--- a/src/Avalonia.Controls.DataGrid/DataGridCell.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGridCell.cs
@@ -19,7 +19,7 @@ namespace Avalonia.Controls
         private Rectangle _rightGridLine;
         private DataGridColumn _owningColumn;
 
-        bool _isValid;
+        bool _isValid = true;
 
         public static readonly DirectProperty<DataGridCell, bool> IsValidProperty =
             AvaloniaProperty.RegisterDirect<DataGridCell, bool>(
@@ -191,7 +191,7 @@ namespace Avalonia.Controls
 
             PseudoClasses.Set(":edited", IsEdited);
 
-            // PseudoClasses.Set(":invalid", !IsValid);
+            PseudoClasses.Set(":invalid", !IsValid);
         }
 
         // Makes sure the right gridline has the proper stroke and visibility. If lastVisibleColumn is specified, the 
diff --git a/src/Avalonia.Controls.DataGrid/DataGridRowGroupHeader.cs b/src/Avalonia.Controls.DataGrid/DataGridRowGroupHeader.cs
index e504fe73a8..0833247439 100644
--- a/src/Avalonia.Controls.DataGrid/DataGridRowGroupHeader.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGridRowGroupHeader.cs
@@ -334,7 +334,7 @@ namespace Avalonia.Controls
         {
             if (_headerElement != null && OwningGrid != null)
             {
-                _headerElement.IsVisible = OwningGrid.AreColumnHeadersVisible;
+                _headerElement.IsVisible = OwningGrid.AreRowHeadersVisible;
             }
         }
 
diff --git a/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml b/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
index 85c1af10ef..94a6274a26 100644
--- a/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
+++ b/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
@@ -7,12 +7,10 @@
                      Color="#3F4346" />
     <SolidColorBrush x:Key="DisabledVisualElementBackground"
                      Color="#8CFFFFFF" />
-    <SolidColorBrush x:Key="InvalidBrush"
-                     Color="#FFFF00" />
     <SolidColorBrush x:Key="FillerGridLinesBrush"
                      Color="Transparent" />
     <StaticResource x:Key="ScrollBarsSeparatorBackground"
-                    ResourceKey="SystemControlPageBackgroundChromeLowBrush" />
+                    ResourceKey="SystemChromeLowColor" />
     <StaticResource x:Key="DataGridColumnHeaderForegroundBrush"
                     ResourceKey="SystemControlForegroundBaseMediumBrush" />
     <StaticResource x:Key="DataGridColumnHeaderBackgroundColor"
@@ -90,7 +88,7 @@
     <StaticResource x:Key="DataGridRowGroupHeaderForegroundBrush"
                     ResourceKey="SystemControlForegroundBaseHighBrush" />
     <StaticResource x:Key="DataGridRowInvalidBrush"
-                    ResourceKey="InvalidBrush" />
+                    ResourceKey="SystemControlErrorTextForegroundBrush" />
     <StaticResource x:Key="DataGridCellBackgroundBrush"
                     ResourceKey="SystemControlTransparentBrush" />
     <StaticResource x:Key="DataGridCellFocusVisualPrimaryBrush"
@@ -98,7 +96,7 @@
     <StaticResource x:Key="DataGridCellFocusVisualSecondaryBrush"
                     ResourceKey="SystemControlFocusVisualSecondaryBrush" />
     <StaticResource x:Key="DataGridCellInvalidBrush"
-                    ResourceKey="InvalidBrush" />
+                    ResourceKey="SystemControlErrorTextForegroundBrush" />
   </Styles.Resources>
 
   <Style Selector="DataGridCell">
@@ -433,7 +431,7 @@
     <Setter Property="MinHeight" Value="32" />
     <Setter Property="Template">
       <ControlTemplate>
-        <DataGridFrozenGrid Name="Root"
+        <DataGridFrozenGrid Name="PART_Root"
                             MinHeight="{TemplateBinding MinHeight}"
                             ColumnDefinitions="Auto,Auto,Auto,Auto,*"
                             RowDefinitions="*,Auto">
@@ -492,11 +490,11 @@
                        StrokeThickness="1" />
           </Grid>
 
-          <DataGridRowHeader Name="RowHeader"
+          <DataGridRowHeader Name="PART_RowHeader"
                              Grid.RowSpan="2"
                              DataGridFrozenGrid.IsFrozen="True" />
 
-          <Rectangle x:Name="BottomGridLine"
+          <Rectangle x:Name="PART_BottomGridLine"
                      Grid.Row="1"
                      Grid.ColumnSpan="5"
                      Height="1" />
@@ -533,13 +531,13 @@
     <Setter Property="Stretch" Value="UniformToFill" />
   </Style>
 
-  <Style Selector="DataGridRowGroupHeader /template/ DataGridFrozenGrid#Root">
+  <Style Selector="DataGridRowGroupHeader /template/ DataGridFrozenGrid#PART_Root">
     <Setter Property="Background" Value="{Binding $parent[DataGridRowGroupHeader].Background}" />
   </Style>
-  <Style Selector="DataGridRowGroupHeader:pointerover /template/ DataGridFrozenGrid#Root">
+  <Style Selector="DataGridRowGroupHeader:pointerover /template/ DataGridFrozenGrid#PART_Root">
     <Setter Property="Background" Value="{DynamicResource DataGridRowGroupHeaderHoveredBackgroundBrush}" />
   </Style>
-  <Style Selector="DataGridRowGroupHeader:pressed /template/ DataGridFrozenGrid#Root">
+  <Style Selector="DataGridRowGroupHeader:pressed /template/ DataGridFrozenGrid#PART_Root">
     <Setter Property="Background" Value="{DynamicResource DataGridRowGroupHeaderPressedBackgroundBrush}" />
   </Style>
 

From 8819b2481e37a64222caac0782914928ee028662 Mon Sep 17 00:00:00 2001
From: Maksym Katsydan <maxkatz6@outlook.com>
Date: Tue, 25 Aug 2020 03:05:47 -0400
Subject: [PATCH 6/8] DataGrid: update samples page

---
 samples/ControlCatalog/Models/GDPValueConverter.cs |  8 ++++----
 samples/ControlCatalog/Models/Person.cs            | 12 ++++++++++++
 samples/ControlCatalog/Pages/DataGridPage.xaml     |  3 ++-
 samples/ControlCatalog/Pages/DataGridPage.xaml.cs  |  2 +-
 4 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/samples/ControlCatalog/Models/GDPValueConverter.cs b/samples/ControlCatalog/Models/GDPValueConverter.cs
index f7975ac604..1ca3e9c8e4 100644
--- a/samples/ControlCatalog/Models/GDPValueConverter.cs
+++ b/samples/ControlCatalog/Models/GDPValueConverter.cs
@@ -19,11 +19,11 @@ namespace ControlCatalog.Models
             if (value is int gdp)
             {
                 if (gdp <= 5000)
-                    return Brushes.Orange;
+                    return new SolidColorBrush(Colors.Orange, 0.6);
                 else if (gdp <= 10000)
-                    return Brushes.Yellow;
+                    return new SolidColorBrush(Colors.Yellow, 0.6);
                 else
-                    return Brushes.LightGreen;
+                    return new SolidColorBrush(Colors.LightGreen, 0.6);
             }
 
             return value;
@@ -34,4 +34,4 @@ namespace ControlCatalog.Models
             throw new NotImplementedException();
         }
     }
-}
\ No newline at end of file
+}
diff --git a/samples/ControlCatalog/Models/Person.cs b/samples/ControlCatalog/Models/Person.cs
index a0abcfe8f4..47f41bc584 100644
--- a/samples/ControlCatalog/Models/Person.cs
+++ b/samples/ControlCatalog/Models/Person.cs
@@ -15,6 +15,7 @@ namespace ControlCatalog.Models
     {
         string _firstName;
         string _lastName;
+        bool _isBanned;
 
         public string FirstName
         {
@@ -47,6 +48,17 @@ namespace ControlCatalog.Models
             }
         }
 
+        public bool IsBanned
+        {
+            get => _isBanned;
+            set
+            {
+                _isBanned = value;
+
+                OnPropertyChanged(nameof(_isBanned));
+            }
+        }
+
         Dictionary<string, List<string>> _errorLookup = new Dictionary<string, List<string>>();
 
         void SetError(string propertyName, string error)
diff --git a/samples/ControlCatalog/Pages/DataGridPage.xaml b/samples/ControlCatalog/Pages/DataGridPage.xaml
index 7b86bba6a9..d045626c2c 100644
--- a/samples/ControlCatalog/Pages/DataGridPage.xaml
+++ b/samples/ControlCatalog/Pages/DataGridPage.xaml
@@ -44,7 +44,8 @@
           <DataGrid Name="dataGridEdit" Margin="12" Grid.Row="0">
             <DataGrid.Columns>
               <DataGridTextColumn Header="First Name" Binding="{Binding FirstName}" Width="2*" />
-              <DataGridTextColumn Header="Last" Binding="{Binding LastName}" Width="*" />
+              <DataGridTextColumn Header="Last" Binding="{Binding LastName}" Width="2*" />
+              <DataGridCheckBoxColumn Header="Is Banned" Binding="{Binding IsBanned}" Width="*" />
             </DataGrid.Columns>
           </DataGrid>
           <Button Grid.Row="1" Name="btnAdd" Margin="12,0,12,12" Content="Add" HorizontalAlignment="Right" />
diff --git a/samples/ControlCatalog/Pages/DataGridPage.xaml.cs b/samples/ControlCatalog/Pages/DataGridPage.xaml.cs
index fea18aa5da..0b7fb12aff 100644
--- a/samples/ControlCatalog/Pages/DataGridPage.xaml.cs
+++ b/samples/ControlCatalog/Pages/DataGridPage.xaml.cs
@@ -33,7 +33,7 @@ namespace ControlCatalog.Pages
             var items = new List<Person>
             {
                 new Person { FirstName = "John", LastName = "Doe" },
-                new Person { FirstName = "Elizabeth", LastName = "Thomas" },
+                new Person { FirstName = "Elizabeth", LastName = "Thomas", IsBanned = true },
                 new Person { FirstName = "Zack", LastName = "Ward" }
             };
             var collectionView3 = new DataGridCollectionView(items);

From 82bd2c487ddaafb69c53d73543385575130a58cf Mon Sep 17 00:00:00 2001
From: Maksym Katsydan <maxkatz6@outlook.com>
Date: Tue, 25 Aug 2020 03:10:31 -0400
Subject: [PATCH 7/8] DataGrid: support hideable scrollbars and some another
 fixes

---
 src/Avalonia.Controls.DataGrid/DataGrid.cs    | 70 ++++++++++++++++---
 .../DataGridColumnHeader.cs                   |  2 +-
 .../DataGridRowHeader.cs                      |  2 +-
 .../Themes/Default.xaml                       |  4 +-
 .../Themes/Fluent.xaml                        | 26 ++++---
 5 files changed, 82 insertions(+), 22 deletions(-)

diff --git a/src/Avalonia.Controls.DataGrid/DataGrid.cs b/src/Avalonia.Controls.DataGrid/DataGrid.cs
index 78c696a3ba..f7903086ab 100644
--- a/src/Avalonia.Controls.DataGrid/DataGrid.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGrid.cs
@@ -39,6 +39,7 @@ namespace Avalonia.Controls
         private const string DATAGRID_elementRowHeadersPresenterName = "PART_RowHeadersPresenter";
         private const string DATAGRID_elementTopLeftCornerHeaderName = "PART_TopLeftCornerHeader";
         private const string DATAGRID_elementTopRightCornerHeaderName = "PART_TopRightCornerHeader";
+        private const string DATAGRID_elementBottomRightCornerHeaderName = "PART_BottomRightCorner";
         private const string DATAGRID_elementValidationSummary = "PART_ValidationSummary";
         private const string DATAGRID_elementVerticalScrollbarName = "PART_VerticalScrollbar";
 
@@ -79,6 +80,7 @@ namespace Avalonia.Controls
         private INotifyCollectionChanged _topLevelGroup;
         private ContentControl _clipboardContentControl;
 
+        private IVisual _bottomRightCorner;
         private DataGridColumnHeadersPresenter _columnHeadersPresenter;
         private DataGridRowsPresenter _rowsPresenter;
         private ScrollBar _vScrollBar;
@@ -1825,6 +1827,22 @@ namespace Avalonia.Controls
             }
         }
 
+        private bool IsHorizontalScrollBarOverCells
+        {
+            get
+            {
+                return _columnHeadersPresenter != null && Grid.GetColumnSpan(_columnHeadersPresenter) == 2;
+            }
+        }
+
+        private bool IsVerticalScrollBarOverCells
+        {
+            get
+            {
+                return _rowsPresenter != null && Grid.GetRowSpan(_rowsPresenter) == 2;
+            }
+        }
+
         private int NoSelectionChangeCount
         {
             get
@@ -2323,6 +2341,7 @@ namespace Avalonia.Controls
             _topLeftCornerHeader = e.NameScope.Find<ContentControl>(DATAGRID_elementTopLeftCornerHeaderName);
             EnsureTopLeftCornerHeader(); // EnsureTopLeftCornerHeader checks for a null _topLeftCornerHeader;
             _topRightCornerHeader = e.NameScope.Find<ContentControl>(DATAGRID_elementTopRightCornerHeaderName);
+            _bottomRightCorner = e.NameScope.Find<IVisual>(DATAGRID_elementBottomRightCornerHeaderName);
         }
 
         /// <summary>
@@ -3293,6 +3312,10 @@ namespace Avalonia.Controls
                 //  
 
             }
+
+            bool isHorizontalScrollBarOverCells = IsHorizontalScrollBarOverCells;
+            bool isVerticalScrollBarOverCells = IsVerticalScrollBarOverCells;
+
             double cellsWidth = CellsWidth;
             double cellsHeight = CellsHeight;
 
@@ -3308,10 +3331,17 @@ namespace Avalonia.Controls
                 // Compensate if the horizontal scrollbar is already taking up space
                 if (!forceHorizScrollbar && _hScrollBar.IsVisible)
                 {
-                    cellsHeight += _hScrollBar.DesiredSize.Height;
+                    if (!isHorizontalScrollBarOverCells)
+                    {
+                        cellsHeight += _hScrollBar.DesiredSize.Height;
+                    }
+                }
+                if (!isHorizontalScrollBarOverCells)
+                {
+                    horizScrollBarHeight = _hScrollBar.Height + _hScrollBar.Margin.Top + _hScrollBar.Margin.Bottom;
                 }
-                horizScrollBarHeight = _hScrollBar.Height + _hScrollBar.Margin.Top + _hScrollBar.Margin.Bottom;
             }
+
             bool allowVertScrollbar = false;
             bool forceVertScrollbar = false;
             double vertScrollBarWidth = 0;
@@ -3324,9 +3354,15 @@ namespace Avalonia.Controls
                 // Compensate if the vertical scrollbar is already taking up space
                 if (!forceVertScrollbar && _vScrollBar.IsVisible)
                 {
-                    cellsWidth += _vScrollBar.DesiredSize.Width;
+                    if (!isVerticalScrollBarOverCells)
+                    {
+                        cellsWidth += _vScrollBar.DesiredSize.Width;
+                    }
+                }
+                if (!isVerticalScrollBarOverCells)
+                {
+                    vertScrollBarWidth = _vScrollBar.Width + _vScrollBar.Margin.Left + _vScrollBar.Margin.Right;
                 }
-                vertScrollBarWidth = _vScrollBar.Width + _vScrollBar.Margin.Left + _vScrollBar.Margin.Right;
             }
 
             // Now cellsWidth is the width potentially available for displaying data cells.
@@ -3354,7 +3390,9 @@ namespace Avalonia.Controls
                     cellsHeight -= horizScrollBarHeight;
                     Debug.Assert(cellsHeight >= 0);
                     needHorizScrollbarWithoutVertScrollbar = needHorizScrollbar = true;
-                    if (allowVertScrollbar && (MathUtilities.LessThanOrClose(totalVisibleWidth - cellsWidth, vertScrollBarWidth) ||
+
+                    if (vertScrollBarWidth > 0 && 
+                        allowVertScrollbar && (MathUtilities.LessThanOrClose(totalVisibleWidth - cellsWidth, vertScrollBarWidth) ||
                         MathUtilities.LessThanOrClose(cellsWidth - totalVisibleFrozenWidth, vertScrollBarWidth)))
                     {
                         // Would we still need a horizontal scrollbar without the vertical one?
@@ -3372,7 +3410,12 @@ namespace Avalonia.Controls
                     }
                 }
 
-                UpdateDisplayedRows(DisplayData.FirstScrollingSlot, cellsHeight);
+                // Store the current FirstScrollingSlot because removing the horizontal scrollbar could scroll
+                // the DataGrid up; however, if we realize later that we need to keep the horizontal scrollbar
+                // then we should use the first slot stored here which is not scrolled.
+                int firstScrollingSlot = DisplayData.FirstScrollingSlot;
+
+                UpdateDisplayedRows(firstScrollingSlot, cellsHeight);
                 if (allowVertScrollbar &&
                     MathUtilities.GreaterThan(cellsHeight, 0) &&
                     MathUtilities.LessThanOrClose(vertScrollBarWidth, cellsWidth) &&
@@ -3384,10 +3427,12 @@ namespace Avalonia.Controls
                 }
 
                 DisplayData.FirstDisplayedScrollingCol = ComputeFirstVisibleScrollingColumn();
+
                 // we compute the number of visible columns only after we set up the vertical scroll bar.
                 ComputeDisplayedColumns();
 
-                if (allowHorizScrollbar &&
+                if ((vertScrollBarWidth > 0 || horizScrollBarHeight > 0) && 
+                    allowHorizScrollbar &&
                     needVertScrollbar && !needHorizScrollbar &&
                     MathUtilities.GreaterThan(totalVisibleWidth, cellsWidth) &&
                     MathUtilities.LessThan(totalVisibleFrozenWidth, cellsWidth) &&
@@ -3398,7 +3443,7 @@ namespace Avalonia.Controls
                     Debug.Assert(cellsHeight >= 0);
                     needVertScrollbar = false;
 
-                    UpdateDisplayedRows(DisplayData.FirstScrollingSlot, cellsHeight);
+                    UpdateDisplayedRows(firstScrollingSlot, cellsHeight);
                     if (cellsHeight > 0 &&
                         vertScrollBarWidth <= cellsWidth &&
                         DisplayData.NumTotallyDisplayedScrollingElements != VisibleSlotCount)
@@ -3479,6 +3524,15 @@ namespace Avalonia.Controls
                     _topRightCornerHeader.IsVisible = false;
                 }
             }
+
+            if (_bottomRightCorner != null)
+            {
+                // Show the BottomRightCorner when both scrollbars are visible.
+                _bottomRightCorner.IsVisible =
+                    _hScrollBar != null && _hScrollBar.IsVisible &&
+                    _vScrollBar != null && _vScrollBar.IsVisible;
+            }
+
             DisplayData.FullyRecycleElements();
         }
 
diff --git a/src/Avalonia.Controls.DataGrid/DataGridColumnHeader.cs b/src/Avalonia.Controls.DataGrid/DataGridColumnHeader.cs
index 767cae7f0b..017718bc92 100644
--- a/src/Avalonia.Controls.DataGrid/DataGridColumnHeader.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGridColumnHeader.cs
@@ -40,7 +40,7 @@ namespace Avalonia.Controls
         private static Cursor _originalCursor;
         private static double _originalHorizontalOffset;
         private static double _originalWidth;
-        private bool _desiredSeparatorVisibility;
+        private bool _desiredSeparatorVisibility = true;
         private static Point? _dragStart;
         private static DataGridColumn _dragColumn;
         private static double _frozenColumnsWidth;
diff --git a/src/Avalonia.Controls.DataGrid/DataGridRowHeader.cs b/src/Avalonia.Controls.DataGrid/DataGridRowHeader.cs
index f046298c61..8f8b1742ba 100644
--- a/src/Avalonia.Controls.DataGrid/DataGridRowHeader.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGridRowHeader.cs
@@ -14,7 +14,7 @@ namespace Avalonia.Controls.Primitives
     /// </summary>
     public class DataGridRowHeader : ContentControl
     {
-        private const string DATAGRIDROWHEADER_elementRootName = "Root";
+        private const string DATAGRIDROWHEADER_elementRootName = "PART_Root";
         private const double DATAGRIDROWHEADER_separatorThickness = 1;
 
         private Control _rootElement;
diff --git a/src/Avalonia.Controls.DataGrid/Themes/Default.xaml b/src/Avalonia.Controls.DataGrid/Themes/Default.xaml
index f7ac0f24e4..93e18548ce 100644
--- a/src/Avalonia.Controls.DataGrid/Themes/Default.xaml
+++ b/src/Avalonia.Controls.DataGrid/Themes/Default.xaml
@@ -139,7 +139,7 @@
   <Style Selector="DataGridRowHeader">
     <Setter Property="Template">
       <ControlTemplate>
-        <Grid
+        <Grid x:Name="PART_Root"
         RowDefinitions="*,*,Auto"
         ColumnDefinitions="Auto,*">
 
@@ -224,7 +224,7 @@
             <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="PART_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}"/>
 
diff --git a/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml b/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
index 94a6274a26..e360de3728 100644
--- a/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
+++ b/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
@@ -2,7 +2,7 @@
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <Styles.Resources>
     <Thickness x:Key="DataGridTextColumnCellTextBlockMargin">12,0,12,0</Thickness>
-    
+
     <SolidColorBrush x:Key="DropLocationIndicatorBackground"
                      Color="#3F4346" />
     <SolidColorBrush x:Key="DisabledVisualElementBackground"
@@ -88,7 +88,7 @@
     <StaticResource x:Key="DataGridRowGroupHeaderForegroundBrush"
                     ResourceKey="SystemControlForegroundBaseHighBrush" />
     <StaticResource x:Key="DataGridRowInvalidBrush"
-                    ResourceKey="SystemControlErrorTextForegroundBrush" />
+                    ResourceKey="SystemErrorTextColor" />
     <StaticResource x:Key="DataGridCellBackgroundBrush"
                     ResourceKey="SystemControlTransparentBrush" />
     <StaticResource x:Key="DataGridCellFocusVisualPrimaryBrush"
@@ -96,7 +96,7 @@
     <StaticResource x:Key="DataGridCellFocusVisualSecondaryBrush"
                     ResourceKey="SystemControlFocusVisualSecondaryBrush" />
     <StaticResource x:Key="DataGridCellInvalidBrush"
-                    ResourceKey="SystemControlErrorTextForegroundBrush" />
+                    ResourceKey="SystemErrorTextColor" />
   </Styles.Resources>
 
   <Style Selector="DataGridCell">
@@ -356,7 +356,7 @@
     <Setter Property="AreSeparatorsVisible" Value="False" />
     <Setter Property="Template">
       <ControlTemplate>
-        <Grid x:Name="PART_RowHeaderRoot"
+        <Grid x:Name="PART_Root"
               RowDefinitions="*,*,Auto"
               ColumnDefinitions="Auto,*">
           <Border Grid.RowSpan="3"
@@ -403,14 +403,14 @@
   <Style Selector="DataGridRowHeader /template/ Rectangle#BackgroundRectangle">
     <Setter Property="Fill" Value="{DynamicResource SystemControlTransparentBrush}" />
   </Style>
-  <Style Selector="DataGridRowHeader:pointerover /template/ Rectangle#BackgroundRectangle">
+  <Style Selector="DataGridRow:pointerover DataGridRowHeader /template/ Rectangle#BackgroundRectangle">
     <Setter Property="Fill" Value="{DynamicResource SystemListLowColor}" />
   </Style>
   <Style Selector="DataGridRowHeader:selected /template/ Rectangle#BackgroundRectangle">
     <Setter Property="Fill" Value="{DynamicResource DataGridRowSelectedUnfocusedBackgroundColor}" />
     <Setter Property="Opacity" Value="{DynamicResource DataGridRowSelectedUnfocusedBackgroundOpacity}" />
   </Style>
-  <Style Selector="DataGridRowHeader:selected:pointerover /template/ Rectangle#BackgroundRectangle">
+  <Style Selector="DataGridRow:pointerover DataGridRowHeader:selected /template/ Rectangle#BackgroundRectangle">
     <Setter Property="Fill" Value="{DynamicResource DataGridRowSelectedHoveredUnfocusedBackgroundColor}" />
     <Setter Property="Opacity" Value="{DynamicResource DataGridRowSelectedHoveredUnfocusedBackgroundOpacity}" />
   </Style>
@@ -418,7 +418,7 @@
     <Setter Property="Fill" Value="{DynamicResource DataGridRowSelectedBackgroundColor}" />
     <Setter Property="Opacity" Value="{DynamicResource DataGridRowSelectedBackgroundOpacity}" />
   </Style>
-  <Style Selector="DataGridRowHeader:selected:pointerover:focus /template/ Rectangle#BackgroundRectangle">
+  <Style Selector="DataGridRow:pointerover DataGridRowHeader:selected:focus /template/ Rectangle#BackgroundRectangle">
     <Setter Property="Fill" Value="{DynamicResource DataGridRowSelectedHoveredBackgroundColor}" />
     <Setter Property="Opacity" Value="{DynamicResource DataGridRowSelectedHoveredBackgroundOpacity}" />
   </Style>
@@ -606,18 +606,24 @@
             <!--<DataGridColumnHeader Name="PART_TopRightCornerHeader"
                                   Grid.Column="2"
                                   Template="{StaticResource TopRightHeaderTemplate}" />-->
-            <Rectangle Name="PART_ColumnHeadersAndRowsSeparator"
+            <!--<Rectangle Name="PART_ColumnHeadersAndRowsSeparator"
                        Grid.ColumnSpan="3"
                        VerticalAlignment="Bottom"
                        StrokeThickness="1"
                        Height="1"
-                       Fill="{DynamicResource GridLinesBrush}" />
+                       Fill="{DynamicResource GridLinesBrush}" />-->
+            <Border Name="PART_ColumnHeadersAndRowsSeparator"
+                    Grid.ColumnSpan="3"
+                    Height="2"
+                    VerticalAlignment="Bottom"
+                    BorderThickness="0,0,0,1"
+                    BorderBrush="{DynamicResource GridLinesBrush}" />
 
             <DataGridRowsPresenter Name="PART_RowsPresenter"
                                    Grid.Row="1"
                                    Grid.RowSpan="2"
                                    Grid.ColumnSpan="3" />
-            <Rectangle Name="BottomRightCorner"
+            <Rectangle Name="PART_BottomRightCorner"
                        Fill="{DynamicResource ScrollBarsSeparatorBackground}"
                        Grid.Column="2"
                        Grid.Row="2" />

From 19e43061b7bd06bf01809547692a54f55830e01a Mon Sep 17 00:00:00 2001
From: Maksym Katsydan <maxkatz6@outlook.com>
Date: Tue, 25 Aug 2020 03:44:21 -0400
Subject: [PATCH 8/8] DataGrid: rename fluent datagrid resources

---
 .../Themes/Fluent.xaml                        | 92 ++++++++-----------
 1 file changed, 37 insertions(+), 55 deletions(-)

diff --git a/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml b/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
index e360de3728..30e33c2b2d 100644
--- a/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
+++ b/src/Avalonia.Controls.DataGrid/Themes/Fluent.xaml
@@ -3,20 +3,33 @@
   <Styles.Resources>
     <Thickness x:Key="DataGridTextColumnCellTextBlockMargin">12,0,12,0</Thickness>
 
-    <SolidColorBrush x:Key="DropLocationIndicatorBackground"
+    <x:Double x:Key="ListAccentLowOpacity">0.6</x:Double>
+    <x:Double x:Key="ListAccentMediumOpacity">0.8</x:Double>
+
+    <StreamGeometry x:Key="DataGridSortIconAscendingPath">M1875 1011l-787 787v-1798h-128v1798l-787 -787l-90 90l941 941l941 -941z</StreamGeometry>
+    <StreamGeometry x:Key="DataGridSortIconDescendingPath">M1965 947l-941 -941l-941 941l90 90l787 -787v1798h128v-1798l787 787z</StreamGeometry>
+    <StreamGeometry x:Key="DataGridRowGroupHeaderIconClosedPath">M515 93l930 931l-930 931l90 90l1022 -1021l-1022 -1021z</StreamGeometry>
+    <StreamGeometry x:Key="DataGridRowGroupHeaderIconOpenedPath">M1939 1581l90 -90l-1005 -1005l-1005 1005l90 90l915 -915z</StreamGeometry>
+
+    <SolidColorBrush x:Key="DataGridGridLinesBrush"
+                     Color="{StaticResource SystemBaseMediumLowColor}"
+                     Opacity="0.4" />
+    <SolidColorBrush x:Key="DataGridDropLocationIndicatorBackground"
                      Color="#3F4346" />
-    <SolidColorBrush x:Key="DisabledVisualElementBackground"
+    <SolidColorBrush x:Key="DataGridDisabledVisualElementBackground"
                      Color="#8CFFFFFF" />
-    <SolidColorBrush x:Key="FillerGridLinesBrush"
+    <SolidColorBrush x:Key="DataGridFillerGridLinesBrush"
+                     Color="Transparent" />
+    <SolidColorBrush x:Key="DataGridCurrencyVisualPrimaryBrush"
                      Color="Transparent" />
-    <StaticResource x:Key="ScrollBarsSeparatorBackground"
-                    ResourceKey="SystemChromeLowColor" />
-    <StaticResource x:Key="DataGridColumnHeaderForegroundBrush"
-                    ResourceKey="SystemControlForegroundBaseMediumBrush" />
     <StaticResource x:Key="DataGridColumnHeaderBackgroundColor"
                     ResourceKey="SystemAltHighColor" />
     <SolidColorBrush x:Key="DataGridColumnHeaderBackgroundBrush"
                      Color="{StaticResource DataGridColumnHeaderBackgroundColor}" />
+    <StaticResource x:Key="DataGridScrollBarsSeparatorBackground"
+                    ResourceKey="SystemChromeLowColor" />
+    <StaticResource x:Key="DataGridColumnHeaderForegroundBrush"
+                    ResourceKey="SystemControlForegroundBaseMediumBrush" />
     <StaticResource x:Key="DataGridColumnHeaderHoveredBackgroundColor"
                     ResourceKey="SystemListLowColor" />
     <StaticResource x:Key="DataGridColumnHeaderPressedBackgroundColor"
@@ -27,38 +40,10 @@
                     ResourceKey="SystemControlHighlightListLowBrush" />
     <StaticResource x:Key="DataGridColumnHeaderPressedBrush"
                     ResourceKey="SystemControlHighlightListMediumBrush" />
-
-    <SolidColorBrush x:Key="SystemControlGridLinesBaseMediumLowBrush"
-                     Color="{StaticResource SystemBaseMediumLowColor}"
-                     Opacity="0.4" />
-    <SolidColorBrush x:Key="SystemControlRowGroupHeaderBackgroundMediumBrush"
-                     Color="{StaticResource SystemChromeMediumColor}" />
-    <SolidColorBrush x:Key="DataGridCurrencyVisualPrimaryBrush"
-                     Color="Transparent" />
-
-    <StreamGeometry x:Key="SortIconAscendingPath">M1875 1011l-787 787v-1798h-128v1798l-787 -787l-90 90l941 941l941 -941z</StreamGeometry>
-    <StreamGeometry x:Key="SortIconDescendingPath">M1965 947l-941 -941l-941 941l90 90l787 -787v1798h128v-1798l787 787z</StreamGeometry>
-    <StreamGeometry x:Key="RowGroupHeaderIconClosedPath">M515 93l930 931l-930 931l90 90l1022 -1021l-1022 -1021z</StreamGeometry>
-    <StreamGeometry x:Key="RowGroupHeaderIconOpenedPath">M1939 1581l90 -90l-1005 -1005l-1005 1005l90 90l915 -915z</StreamGeometry>
-
-    <!--<x:String x:Key="ScrollBarsSeparatorExpandBeginTime">00:00:00.40</x:String>
-    <x:String x:Key="ScrollBarsSeparatorExpandDuration">00:00:00.1</x:String>
-    <x:String x:Key="ScrollBarsSeparatorContractBeginTime">00:00:02.00</x:String>
-    <x:String x:Key="ScrollBarsSeparatorContractDelay">00:00:02</x:String>
-    <x:String x:Key="ScrollBarsSeparatorContractDuration">00:00:00.1</x:String>
-    <x:String x:Key="ScrollBarsSeparatorContractFinalKeyframe">00:00:02.1</x:String>
-    <x:String x:Key="ScrollBarsSeparatorNoTouchDuration">00:00:00.5</x:String>-->
-
-    <x:Double x:Key="ListAccentLowOpacity">0.6</x:Double>
-    <x:Double x:Key="ListAccentMediumOpacity">0.8</x:Double>
-
-    <StaticResource x:Key="GridLinesBrush"
-                    ResourceKey="SystemControlGridLinesBaseMediumLowBrush" />
-
     <StaticResource x:Key="DataGridDetailsPresenterBackgroundBrush"
                     ResourceKey="SystemControlBackgroundChromeMediumLowBrush" />
     <StaticResource x:Key="DataGridFillerColumnGridLinesBrush"
-                    ResourceKey="FillerGridLinesBrush" />
+                    ResourceKey="DataGridFillerGridLinesBrush" />
     <StaticResource x:Key="DataGridRowSelectedBackgroundColor"
                     ResourceKey="SystemAccentColor" />
     <StaticResource x:Key="DataGridRowSelectedBackgroundOpacity"
@@ -185,7 +170,7 @@
     <Setter Property="HorizontalContentAlignment" Value="Stretch" />
     <Setter Property="VerticalContentAlignment" Value="Center" />
     <Setter Property="Focusable" Value="False" />
-    <Setter Property="SeparatorBrush" Value="{DynamicResource GridLinesBrush}" />
+    <Setter Property="SeparatorBrush" Value="{DynamicResource DataGridGridLinesBrush}" />
     <Setter Property="Padding" Value="12,0,0,0" />
     <Setter Property="FontSize" Value="12" />
     <Setter Property="MinHeight" Value="32" />
@@ -252,9 +237,6 @@
     <Setter Property="IsVisible" Value="True" />
   </Style>
 
-  <Style Selector="DataGridColumnHeader /template/ Grid#PART_ColumnHeaderRoot">
-    <Setter Property="Background" Value="{DynamicResource DataGridColumnHeaderBackgroundColor}" />
-  </Style>
   <Style Selector="DataGridColumnHeader:pointerover /template/ Grid#PART_ColumnHeaderRoot">
     <Setter Property="Background" Value="{DynamicResource DataGridColumnHeaderHoveredBackgroundColor}" />
   </Style>
@@ -272,12 +254,12 @@
 
   <Style Selector="DataGridColumnHeader:sortascending /template/ Path#SortIcon">
     <Setter Property="IsVisible" Value="True" />
-    <Setter Property="Data" Value="{StaticResource SortIconAscendingPath}" />
+    <Setter Property="Data" Value="{StaticResource DataGridSortIconAscendingPath}" />
   </Style>
 
   <Style Selector="DataGridColumnHeader:sortdescending /template/ Path#SortIcon">
     <Setter Property="IsVisible" Value="True" />
-    <Setter Property="Data" Value="{StaticResource SortIconDescendingPath}" />
+    <Setter Property="Data" Value="{StaticResource DataGridSortIconDescendingPath}" />
   </Style>
 
   <Style Selector="DataGridRow">
@@ -352,7 +334,7 @@
   <Style Selector="DataGridRowHeader">
     <Setter Property="Background" Value="{DynamicResource DataGridRowHeaderBackgroundBrush}" />
     <Setter Property="Focusable" Value="False" />
-    <Setter Property="SeparatorBrush" Value="{DynamicResource GridLinesBrush}" />
+    <Setter Property="SeparatorBrush" Value="{DynamicResource DataGridGridLinesBrush}" />
     <Setter Property="AreSeparatorsVisible" Value="False" />
     <Setter Property="Template">
       <ControlTemplate>
@@ -522,12 +504,12 @@
   </Style>
 
   <Style Selector="DataGridRowGroupHeader /template/ ToggleButton#ExpanderButton /template/ Path">
-    <Setter Property="Data" Value="{StaticResource RowGroupHeaderIconOpenedPath}" />
+    <Setter Property="Data" Value="{StaticResource DataGridRowGroupHeaderIconOpenedPath}" />
     <Setter Property="Stretch" Value="Uniform" />
   </Style>
 
   <Style Selector="DataGridRowGroupHeader /template/ ToggleButton#ExpanderButton:checked /template/ Path">
-    <Setter Property="Data" Value="{StaticResource RowGroupHeaderIconClosedPath}" />
+    <Setter Property="Data" Value="{StaticResource DataGridRowGroupHeaderIconClosedPath}" />
     <Setter Property="Stretch" Value="UniformToFill" />
   </Style>
 
@@ -562,11 +544,11 @@
     <Setter Property="VerticalScrollBarVisibility" Value="Auto" />
     <Setter Property="SelectionMode" Value="Extended" />
     <Setter Property="GridLinesVisibility" Value="None" />
-    <Setter Property="HorizontalGridLinesBrush" Value="{DynamicResource GridLinesBrush}" />
-    <Setter Property="VerticalGridLinesBrush" Value="{DynamicResource GridLinesBrush}" />
+    <Setter Property="HorizontalGridLinesBrush" Value="{DynamicResource DataGridGridLinesBrush}" />
+    <Setter Property="VerticalGridLinesBrush" Value="{DynamicResource DataGridGridLinesBrush}" />
     <Setter Property="DropLocationIndicatorTemplate">
       <Template>
-        <Rectangle Fill="{DynamicResource DropLocationIndicatorBackground}"
+        <Rectangle Fill="{DynamicResource DataGridDropLocationIndicatorBackground}"
                    Width="2" />
       </Template>
     </Setter>
@@ -584,12 +566,12 @@
                       RowDefinitions="*,*,Auto">
                   <Border Grid.RowSpan="2"
                           BorderThickness="0,0,1,0"
-                          BorderBrush="{DynamicResource GridLinesBrush}" />
+                          BorderBrush="{DynamicResource DataGridGridLinesBrush}" />
                   <Rectangle Grid.RowSpan="2"
                              VerticalAlignment="Bottom"
                              StrokeThickness="1"
                              Height="1"
-                             Fill="{DynamicResource GridLinesBrush}" />
+                             Fill="{DynamicResource DataGridGridLinesBrush}" />
                 </Grid>
               </ControlTemplate>
               <ControlTemplate x:Key="TopRightHeaderTemplate"
@@ -611,24 +593,24 @@
                        VerticalAlignment="Bottom"
                        StrokeThickness="1"
                        Height="1"
-                       Fill="{DynamicResource GridLinesBrush}" />-->
+                       Fill="{DynamicResource DataGridGridLinesBrush}" />-->
             <Border Name="PART_ColumnHeadersAndRowsSeparator"
                     Grid.ColumnSpan="3"
                     Height="2"
                     VerticalAlignment="Bottom"
                     BorderThickness="0,0,0,1"
-                    BorderBrush="{DynamicResource GridLinesBrush}" />
+                    BorderBrush="{DynamicResource DataGridGridLinesBrush}" />
 
             <DataGridRowsPresenter Name="PART_RowsPresenter"
                                    Grid.Row="1"
                                    Grid.RowSpan="2"
                                    Grid.ColumnSpan="3" />
             <Rectangle Name="PART_BottomRightCorner"
-                       Fill="{DynamicResource ScrollBarsSeparatorBackground}"
+                       Fill="{DynamicResource DataGridScrollBarsSeparatorBackground}"
                        Grid.Column="2"
                        Grid.Row="2" />
             <!--<Rectangle Name="BottomLeftCorner"
-                       Fill="{DynamicResource ScrollBarsSeparatorBackground}"
+                       Fill="{DynamicResource DataGridScrollBarsSeparatorBackground}"
                        Grid.Row="2"
                        Grid.ColumnSpan="2" />-->
             <ScrollBar Name="PART_VerticalScrollbar"
@@ -653,7 +635,7 @@
                     HorizontalAlignment="Stretch"
                     VerticalAlignment="Stretch"
                     CornerRadius="2"
-                    Background="{DynamicResource DisabledVisualElementBackground}"
+                    Background="{DynamicResource DataGridDisabledVisualElementBackground}"
                     IsVisible="{Binding !$parent[DataGrid].IsEnabled}" />
           </Grid>
         </Border>