From b7a22374428ac82cdd416f6d8f1c86534d65a933 Mon Sep 17 00:00:00 2001
From: Brett Story <brettmstory@gmail.com>
Date: Sun, 16 Jan 2022 13:44:30 -0600
Subject: [PATCH] Alternating ListBox control

---
 AvaloniaEx/Controls/AlternatingListBox.cs     | 57 +++++++++++++++++++
 AvaloniaEx/Theme/Accents/Base.axaml           |  1 +
 AvaloniaEx/Theme/Base.axaml                   |  2 +-
 .../Theme/Controls/AlternatingListBox.axaml   | 36 ++++++++++++
 AvaloniaEx/Theme/Controls/ListBoxItem.axaml   | 50 ++++++++--------
 Sample/Views/MainWindow.axaml                 |  4 +-
 6 files changed, 122 insertions(+), 28 deletions(-)
 create mode 100644 AvaloniaEx/Controls/AlternatingListBox.cs
 create mode 100644 AvaloniaEx/Theme/Controls/AlternatingListBox.axaml

diff --git a/AvaloniaEx/Controls/AlternatingListBox.cs b/AvaloniaEx/Controls/AlternatingListBox.cs
new file mode 100644
index 0000000..152410a
--- /dev/null
+++ b/AvaloniaEx/Controls/AlternatingListBox.cs
@@ -0,0 +1,57 @@
+namespace Macabresoft.AvaloniaEx;
+
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Controls.Generators;
+using Avalonia.Controls.Primitives;
+using Avalonia.Data;
+using Avalonia.Media;
+
+/// <summary>
+/// A <see cref="ListBox"/> with alternating row colors.
+/// </summary>
+public sealed class AlternatingListBox : ListBox {
+    /// <summary>
+    /// The alternate background property.
+    /// </summary>
+    public static readonly StyledProperty<IBrush> AlternateBackgroundProperty =
+        AvaloniaProperty.Register<AlternatingListBox, IBrush>(nameof(AlternateBackground));
+    
+    /// <summary>
+    /// Gets or sets the alternate background color to be used on every other row.
+    /// </summary>
+    public IBrush AlternateBackground {
+        get => this.GetValue(AlternateBackgroundProperty);
+        set => this.SetValue(AlternateBackgroundProperty, value);
+    }
+    
+    /// <inheritdoc />
+    protected override IItemContainerGenerator CreateItemContainerGenerator() {
+        return new AlternatingListBoxItemGenerator(this);    
+    }
+    
+    private sealed class AlternatingListBoxItemGenerator : ItemContainerGenerator<ListBoxItem> {
+        private readonly AlternatingListBox _owner;
+        private bool _useAlternateColor;
+        
+        /// <summary>
+        /// Initializes a new instance of the <see cref="AlternatingListBoxItemGenerator" /> class.
+        /// </summary>
+        /// <param name="owner">The owner.</param>
+        public AlternatingListBoxItemGenerator(AlternatingListBox owner) : base(owner, ContentControl.ContentProperty, ContentControl.ContentTemplateProperty) {
+            this._owner = owner;
+        }
+
+        /// <inheritdoc />
+        protected override IControl CreateContainer(object item) {
+            var result = base.CreateContainer(item);
+            if (this._useAlternateColor && result is ListBoxItem listBoxItem) {
+                result.SetValue(TemplatedControl.BackgroundProperty, this._owner.AlternateBackground);
+            }
+
+            this._useAlternateColor = !this._useAlternateColor;
+            return result;
+        }
+    }
+}
+
diff --git a/AvaloniaEx/Theme/Accents/Base.axaml b/AvaloniaEx/Theme/Accents/Base.axaml
index 1b6f62e..6543192 100644
--- a/AvaloniaEx/Theme/Accents/Base.axaml
+++ b/AvaloniaEx/Theme/Accents/Base.axaml
@@ -47,5 +47,6 @@
         <SolidColorBrush x:Key="DarkYellowBrush" Color="#735D23" />
         <SolidColorBrush x:Key="WhiteBrush" Color="{StaticResource SystemBaseHighColor}" />
         <SolidColorBrush x:Key="SystemAccentBrush" Color="{StaticResource SystemAccentColor}" />
+        <SolidColorBrush x:Key="AlternateListBoxItemBackgroundColor" Color="#28FFFFFF" />
     </Style.Resources>
 </Style>
\ No newline at end of file
diff --git a/AvaloniaEx/Theme/Base.axaml b/AvaloniaEx/Theme/Base.axaml
index 27751c3..afafcbd 100644
--- a/AvaloniaEx/Theme/Base.axaml
+++ b/AvaloniaEx/Theme/Base.axaml
@@ -6,6 +6,7 @@
     <StyleInclude Source="avares://Macabresoft.AvaloniaEx/Theme/BoxShadows.axaml" />
     <StyleInclude Source="avares://Macabresoft.AvaloniaEx/Theme/IconPaths.axaml" />
 
+    <StyleInclude Source="avares://Macabresoft.AvaloniaEx/Theme/Controls/AlternatingListBox.axaml" />
     <StyleInclude Source="avares://Macabresoft.AvaloniaEx/Theme/Controls/AutoCompleteBox.axaml" />
     <StyleInclude Source="avares://Macabresoft.AvaloniaEx/Theme/Controls/Border.axaml" />
     <StyleInclude Source="avares://Macabresoft.AvaloniaEx/Theme/Controls/Button.axaml" />
@@ -26,5 +27,4 @@
     <StyleInclude Source="avares://Macabresoft.AvaloniaEx/Theme/Controls/TreeView.axaml" />
     <StyleInclude Source="avares://Macabresoft.AvaloniaEx/Theme/Controls/TreeViewItem.axaml" />
     <StyleInclude Source="avares://Macabresoft.AvaloniaEx/Theme/Controls/Window.axaml" />
-
 </Styles>
\ No newline at end of file
diff --git a/AvaloniaEx/Theme/Controls/AlternatingListBox.axaml b/AvaloniaEx/Theme/Controls/AlternatingListBox.axaml
new file mode 100644
index 0000000..cb49b46
--- /dev/null
+++ b/AvaloniaEx/Theme/Controls/AlternatingListBox.axaml
@@ -0,0 +1,36 @@
+<Styles xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:avaloniaEx="clr-namespace:Macabresoft.AvaloniaEx">
+    <Style Selector="avaloniaEx|AlternatingListBox">
+        <Setter Property="TextBlock.Foreground" Value="{StaticResource SystemControlForegroundBaseHighBrush}" />
+        <Setter Property="Background" Value="Transparent" />
+        <Setter Property="AlternateBackground" Value="{StaticResource AlternateListBoxItemBackgroundColor}" />
+        <Setter Property="BorderBrush" Value="{StaticResource SystemControlForegroundBaseHighBrush}" />
+        <Setter Property="BorderThickness" Value="{StaticResource ListBoxBorderThemeThickness}" />
+        <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Disabled" />
+        <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto" />        
+        <Setter Property="FontSize" Value="{StaticResource ControlContentThemeFontSize}" />
+        <Setter Property="Margin" Value="{StaticResource StandardMarginAll}" />
+        <Setter Property="Template">
+            <ControlTemplate>
+                <Border Name="border"
+                        Background="{TemplateBinding Background}"
+                        BorderBrush="{TemplateBinding BorderBrush}"
+                        BorderThickness="{TemplateBinding BorderThickness}"
+                        CornerRadius="{TemplateBinding CornerRadius}">
+                    <ScrollViewer Name="PART_ScrollViewer"
+                                  HorizontalScrollBarVisibility="{TemplateBinding (ScrollViewer.HorizontalScrollBarVisibility)}"
+                                  VerticalScrollBarVisibility="{TemplateBinding (ScrollViewer.VerticalScrollBarVisibility)}"
+                                  AllowAutoHide="{TemplateBinding (ScrollViewer.AllowAutoHide)}">
+                        <ItemsPresenter Name="PART_ItemsPresenter"
+                                        Items="{TemplateBinding Items}"
+                                        ItemsPanel="{TemplateBinding ItemsPanel}"
+                                        ItemTemplate="{TemplateBinding ItemTemplate}"
+                                        Margin="{TemplateBinding Padding}"
+                                        VirtualizationMode="{TemplateBinding VirtualizationMode}"/>
+                    </ScrollViewer>
+                </Border>
+            </ControlTemplate>
+        </Setter>
+    </Style>
+</Styles>
\ No newline at end of file
diff --git a/AvaloniaEx/Theme/Controls/ListBoxItem.axaml b/AvaloniaEx/Theme/Controls/ListBoxItem.axaml
index 932af39..394ca2e 100644
--- a/AvaloniaEx/Theme/Controls/ListBoxItem.axaml
+++ b/AvaloniaEx/Theme/Controls/ListBoxItem.axaml
@@ -1,68 +1,68 @@
 <Styles xmlns="https://github.com/avaloniaui"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
     <Style Selector="ListBoxItem">
-        <Setter Property="Background" Value="{DynamicResource TreeViewItemBackground}" />
-        <Setter Property="BorderBrush" Value="{DynamicResource TreeViewItemBorderBrush}" />
-        <Setter Property="BorderThickness" Value="{DynamicResource TreeViewItemBorderThemeThickness}" />
-        <Setter Property="Foreground" Value="{DynamicResource TreeViewItemForeground}" />
-        <Setter Property="MinHeight" Value="{DynamicResource TreeViewItemMinHeight}" />
-        <Setter Property="Padding" Value="16,0,0,0" />
+        <Setter Property="Background" Value="{StaticResource TreeViewItemBackground}" />
+        <Setter Property="BorderBrush" Value="{StaticResource TreeViewItemBorderBrush}" />
+        <Setter Property="BorderThickness" Value="{StaticResource TreeViewItemBorderThemeThickness}" />
+        <Setter Property="Foreground" Value="{StaticResource TreeViewItemForeground}" />
+        <Setter Property="MinHeight" Value="{StaticResource TreeViewItemMinHeight}" />
+        <Setter Property="Padding" Value="{StaticResource StandardMarginAll}" />
         <Setter Property="VerticalContentAlignment" Value="Center" />
         <Setter Property="HorizontalContentAlignment" Value="Stretch" />
     </Style>
 
     <Style Selector="ListBoxItem /template/ ContentPresenter#PART_ContentPresenter">
-        <Setter Property="CornerRadius" Value="{DynamicResource ControlCornerRadius}" />
+        <Setter Property="CornerRadius" Value="{StaticResource ControlCornerRadius}" />
     </Style>
 
     <!--  Disabled State  -->
     <Style Selector="ListBoxItem:disabled /template/ ContentPresenter#PART_ContentPresenter">
-        <Setter Property="Background" Value="{DynamicResource TreeViewItemBackgroundDisabled}" />
-        <Setter Property="BorderBrush" Value="{DynamicResource TreeViewItemBorderBrushDisabled}" />
-        <Setter Property="TextBlock.Foreground" Value="{DynamicResource TreeViewItemForegroundDisabled}" />
+        <Setter Property="Background" Value="{StaticResource TreeViewItemBackgroundDisabled}" />
+        <Setter Property="BorderBrush" Value="{StaticResource TreeViewItemBorderBrushDisabled}" />
+        <Setter Property="TextBlock.Foreground" Value="{StaticResource TreeViewItemForegroundDisabled}" />
     </Style>
 
     <!--  PointerOver State  -->
     <Style Selector="ListBoxItem:pointerover /template/ ContentPresenter#PART_ContentPresenter">
-        <Setter Property="Background" Value="{DynamicResource TreeViewItemBackgroundPointerOver}" />
-        <Setter Property="BorderBrush" Value="{DynamicResource TreeViewItemBorderBrushPointerOver}" />
-        <Setter Property="TextBlock.Foreground" Value="{DynamicResource TreeViewItemForegroundPointerOver}" />
+        <Setter Property="Background" Value="{StaticResource TreeViewItemBackgroundPointerOver}" />
+        <Setter Property="BorderBrush" Value="{StaticResource TreeViewItemBorderBrushPointerOver}" />
+        <Setter Property="TextBlock.Foreground" Value="{StaticResource TreeViewItemForegroundPointerOver}" />
     </Style>
 
     <!--  Pressed State  -->
     <Style Selector="ListBoxItem:pressed /template/ ContentPresenter#PART_ContentPresenter">
-        <Setter Property="Background" Value="{DynamicResource TreeViewItemBackgroundPressed}" />
-        <Setter Property="BorderBrush" Value="{DynamicResource TreeViewItemBorderBrushPressed}" />
+        <Setter Property="Background" Value="{StaticResource TreeViewItemBackgroundPressed}" />
+        <Setter Property="BorderBrush" Value="{StaticResource TreeViewItemBorderBrushPressed}" />
     </Style>
     <Style Selector="ListBoxItem:pressed /template/ ContentPresenter">
-        <Setter Property="TextBlock.Foreground" Value="{DynamicResource TreeViewItemForegroundPressed}" />
+        <Setter Property="TextBlock.Foreground" Value="{StaticResource TreeViewItemForegroundPressed}" />
     </Style>
 
     <!--  Selected State  -->
     <Style Selector="ListBoxItem:selected /template/ ContentPresenter#PART_ContentPresenter">
-        <Setter Property="Background" Value="{DynamicResource TreeViewItemBackgroundSelected}" />
-        <Setter Property="BorderBrush" Value="{DynamicResource TreeViewItemBorderBrushSelected}" />
+        <Setter Property="Background" Value="{StaticResource TreeViewItemBackgroundSelected}" />
+        <Setter Property="BorderBrush" Value="{StaticResource TreeViewItemBorderBrushSelected}" />
     </Style>
     <Style Selector="ListBoxItem:selected /template/ ContentPresenter">
-        <Setter Property="TextBlock.Foreground" Value="{DynamicResource TreeViewItemForegroundSelected}" />
+        <Setter Property="TextBlock.Foreground" Value="{StaticResource TreeViewItemForegroundSelected}" />
     </Style>
 
     <!--  Selected PointerOver State  -->
     <Style Selector="ListBoxItem:selected:pointerover /template/ ContentPresenter#PART_ContentPresenter">
-        <Setter Property="Background" Value="{DynamicResource TreeViewItemBackgroundSelectedPointerOver}" />
-        <Setter Property="BorderBrush" Value="{DynamicResource TreeViewItemBorderBrushSelectedPointerOver}" />
+        <Setter Property="Background" Value="{StaticResource TreeViewItemBackgroundSelectedPointerOver}" />
+        <Setter Property="BorderBrush" Value="{StaticResource TreeViewItemBorderBrushSelectedPointerOver}" />
     </Style>
     <Style Selector="ListBoxItem:selected:pointerover /template/ ContentPresenter">
-        <Setter Property="TextBlock.Foreground" Value="{DynamicResource TreeViewItemForegroundSelectedPointerOver}" />
+        <Setter Property="TextBlock.Foreground" Value="{StaticResource TreeViewItemForegroundSelectedPointerOver}" />
     </Style>
 
     <!--  Selected Pressed State  -->
     <Style Selector="ListBoxItem:selected:pressed /template/ ContentPresenter#PART_ContentPresenter">
-        <Setter Property="Background" Value="{DynamicResource TreeViewItemBackgroundSelectedPressed}" />
-        <Setter Property="BorderBrush" Value="{DynamicResource TreeViewItemBorderBrushSelectedPressed}" />
+        <Setter Property="Background" Value="{StaticResource TreeViewItemBackgroundSelectedPressed}" />
+        <Setter Property="BorderBrush" Value="{StaticResource TreeViewItemBorderBrushSelectedPressed}" />
     </Style>
     <Style Selector="ListBoxItem:selected:pressed /template/ ContentPresenter#PART_ContentPresenter">
-        <Setter Property="TextBlock.Foreground" Value="{DynamicResource TreeViewItemForegroundSelectedPressed}" />
+        <Setter Property="TextBlock.Foreground" Value="{StaticResource TreeViewItemForegroundSelectedPressed}" />
     </Style>
 
 
diff --git a/Sample/Views/MainWindow.axaml b/Sample/Views/MainWindow.axaml
index 542abd3..a8e70fc 100644
--- a/Sample/Views/MainWindow.axaml
+++ b/Sample/Views/MainWindow.axaml
@@ -158,8 +158,8 @@
                 <TextBlock Classes="Label"
                            Text="A Curious List"
                            Foreground="{StaticResource YellowBrush}"/>
-                <ListBox Grid.Row="1"
-                         Items="{Binding List}" />
+                <avaloniaEx:AlternatingListBox Grid.Row="1"
+                                               Items="{Binding List}" />
             </Grid>
         </Border>
     </Grid>