Merge pull request #8568 from AvaloniaUI/datagrid-control-theme

Add DataGrid fluent Control Theme

samples/ControlCatalog/Pages/DataGridPage.xaml

@@ -10,11 +10,11 @@
         <TextBlock Text="{Binding}"/>
       </StackPanel>
     </DataTemplate>
+    <ControlTheme x:Key="GdpCell" TargetType="DataGridCell" BasedOn="{StaticResource {x:Type DataGridCell}}">
+      <Setter Property="Background" Value="{Binding Path=GDP, Mode=OneWay, Converter={StaticResource GDPConverter}}" />
+    </ControlTheme>
   </UserControl.Resources>
   <UserControl.Styles>
-    <Style Selector="DataGridCell.gdp">
-      <Setter Property="Background" Value="{Binding Path=GDP, Mode=OneWay, Converter={StaticResource GDPConverter}}" />
-    </Style>
     <Style Selector="DataGridColumnHeader:nth-last-child(1)">
       <Setter Property="FontWeight" Value="Bold" />
     </Style>
@@ -54,7 +54,8 @@
               <DataGridTextColumn Header="Region" Binding="{CompiledBinding Region}" Width="4*" x:DataType="local:Country" />
               <DataGridTextColumn Header="Population" Binding="{Binding Population}" Width="3*" />
               <DataGridTextColumn Header="Area" Binding="{Binding Area}" Width="3*" />
-              <DataGridTextColumn Header="GDP" Binding="{Binding GDP}" Width="3*" CellStyleClasses="gdp"
+              <DataGridTextColumn Header="GDP" Binding="{Binding GDP}" Width="3*"
+                                  CellTheme="{StaticResource GdpCell}"
                                   MinWidth="200"
                                   IsVisible="{Binding #ShowGDP.IsChecked}"/>
             </DataGrid.Columns>

src/Avalonia.Controls.DataGrid/DataGridCell.cs

@@ -14,7 +14,7 @@ namespace Avalonia.Controls
     /// Represents an individual <see cref="T:Avalonia.Controls.DataGrid" /> cell.
     /// </summary>
     [TemplatePart(DATAGRIDCELL_elementRightGridLine, typeof(Rectangle))]
-    [PseudoClasses(":selected", ":current", ":edited", ":invalid")]
+    [PseudoClasses(":selected", ":current", ":edited", ":invalid", ":focus")]
     public class DataGridCell : ContentControl
     {
         private const string DATAGRIDCELL_elementRightGridLine = "PART_RightGridLine";
@@ -216,6 +216,8 @@ namespace Avalonia.Controls
             PseudoClasses.Set(":edited", IsEdited);
 
             PseudoClasses.Set(":invalid", !IsValid);
+            
+            PseudoClasses.Set(":focus", OwningGrid.IsFocused && IsCurrent);
         }
 
         // Makes sure the right gridline has the proper stroke and visibility. If lastVisibleColumn is specified, the 
@@ -245,9 +247,15 @@ namespace Avalonia.Controls
             if (column == null)
             {
                 Classes.Clear();
+                ClearValue(ThemeProperty);
             }
             else
             {
+                if (Theme != column.CellTheme)
+                {
+                    Theme = column.CellTheme;
+                }
+                
                 Classes.Replace(column.CellStyleClasses);
             }
         }

src/Avalonia.Controls.DataGrid/DataGridColumn.cs

@@ -16,6 +16,7 @@ using Avalonia.Controls.Templates;
 using Avalonia.Controls.Utils;
 using Avalonia.Layout;
 using Avalonia.Markup.Xaml.MarkupExtensions;
+using Avalonia.Styling;
 
 namespace Avalonia.Controls
 {
@@ -36,6 +37,7 @@ namespace Avalonia.Controls
         private IControl _editingElement;
         private ICellEditBinding _editBinding;
         private IBinding _clipboardContentBinding;
+        private ControlTheme _cellTheme;
         private readonly Classes _cellStyleClasses = new Classes();
 
         /// <summary>
@@ -399,6 +401,24 @@ namespace Avalonia.Controls
                 }
             }
         }
+        
+        /// <summary>
+        ///    Backing field for CellTheme property.
+        /// </summary>
+        public static readonly DirectProperty<DataGridColumn, ControlTheme> CellThemeProperty =
+            AvaloniaProperty.RegisterDirect<DataGridColumn, ControlTheme>(
+                nameof(CellTheme),
+                o => o.CellTheme,
+                (o, v) => o.CellTheme = v);
+
+        /// <summary>
+        ///    Gets or sets the <see cref="DataGridColumnHeader"/> cell theme. 
+        /// </summary>
+        public ControlTheme CellTheme
+        {
+            get { return _cellTheme; }
+            set { SetAndRaise(CellThemeProperty, ref _cellTheme, value); }
+        }
 
         /// <summary>
         ///    Backing field for Header property

src/Avalonia.Controls.DataGrid/DataGridRowGroupHeader.cs

@@ -113,7 +113,6 @@ namespace Avalonia.Controls
         /// </summary>
         public DataGridRowGroupHeader()
         {
-            //DefaultStyleKey = typeof(DataGridRowGroupHeader);
             AddHandler(InputElement.PointerPressedEvent, (s, e) => DataGridRowGroupHeader_PointerPressed(e), handledEventsToo: true);
         }
 

src/Avalonia.Controls.DataGrid/DataGridTextColumn.cs

@@ -11,6 +11,7 @@ using System.ComponentModel;
 using Avalonia.Layout;
 using Avalonia.Markup.Xaml.MarkupExtensions;
 using Avalonia.Controls.Documents;
+using Avalonia.Styling;
 
 namespace Avalonia.Controls
 {
@@ -19,12 +20,20 @@ namespace Avalonia.Controls
     /// </summary>
     public class DataGridTextColumn : DataGridBoundColumn
     {
+        private readonly Lazy<ControlTheme> _cellTextBoxTheme;
+        private readonly Lazy<ControlTheme> _cellTextBlockTheme;
+        
         /// <summary>
         /// Initializes a new instance of the <see cref="T:Avalonia.Controls.DataGridTextColumn" /> class.
         /// </summary>
         public DataGridTextColumn()
         {
             BindingTarget = TextBox.TextProperty;
+
+            _cellTextBoxTheme = new Lazy<ControlTheme>(() =>
+                OwningGrid.TryFindResource("DataGridCellTextBoxTheme", out var theme) ? (ControlTheme)theme : null);
+            _cellTextBlockTheme = new Lazy<ControlTheme>(() =>
+                OwningGrid.TryFindResource("DataGridCellTextBlockTheme", out var theme) ? (ControlTheme)theme : null);
         }
 
         /// <summary>
@@ -156,16 +165,19 @@ namespace Avalonia.Controls
         protected override IControl GenerateEditingElementDirect(DataGridCell cell, object dataItem)
         {
             var textBox = new TextBox
-            {
-                VerticalAlignment = VerticalAlignment.Stretch,
-                Background = new SolidColorBrush(Colors.Transparent)
+            {                
+                Name = "CellTextBox"
             };
+            if (_cellTextBoxTheme.Value is { } theme)
+            {
+                textBox.Theme = theme;
+            }
 
             SyncProperties(textBox);
 
             return textBox;
         }
-
+        
         /// <summary>
         /// Gets a read-only <see cref="T:Avalonia.Controls.TextBlock" /> element that is bound to the column's <see cref="P:Avalonia.Controls.DataGridBoundColumn.Binding" /> property value.
         /// </summary>
@@ -174,10 +186,14 @@ namespace Avalonia.Controls
         /// <returns>A new, read-only <see cref="T:Avalonia.Controls.TextBlock" /> element that is bound to the column's <see cref="P:Avalonia.Controls.DataGridBoundColumn.Binding" /> property value.</returns>
         protected override IControl GenerateElement(DataGridCell cell, object dataItem)
         {
-            TextBlock textBlockElement = new TextBlock
+            var textBlockElement = new TextBlock
             {
                 Name = "CellTextBlock"
             };
+            if (_cellTextBlockTheme.Value is { } theme)
+            {
+                textBlockElement.Theme = theme;
+            }
 
             SyncProperties(textBlockElement);
 
@@ -227,7 +243,7 @@ namespace Avalonia.Controls
         {
             if (element == null)
             {
-                throw new ArgumentNullException("element");
+                throw new ArgumentNullException(nameof(element));
             }
 
             if (element is AvaloniaObject content)