From 4120f59c9046ef67572fe39907f4b084e07a0acc Mon Sep 17 00:00:00 2001
From: Dong Bin <popmessiah@hotmail.com>
Date: Mon, 14 Apr 2025 01:21:20 +0800
Subject: [PATCH] feat: use multibinding for TreeViewItem indentation.

---
 src/Semi.Avalonia/Controls/TreeView.axaml     | 28 +++++++++----------
 .../Converters/TreeViewItemIndentConverter.cs | 25 +++++++++++++++++
 2 files changed, 39 insertions(+), 14 deletions(-)
 create mode 100644 src/Semi.Avalonia/Converters/TreeViewItemIndentConverter.cs

diff --git a/src/Semi.Avalonia/Controls/TreeView.axaml b/src/Semi.Avalonia/Controls/TreeView.axaml
index 43eae95..5d04527 100644
--- a/src/Semi.Avalonia/Controls/TreeView.axaml
+++ b/src/Semi.Avalonia/Controls/TreeView.axaml
@@ -1,7 +1,7 @@
 <ResourceDictionary
     xmlns="https://github.com/avaloniaui"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-    xmlns:converters="clr-namespace:Avalonia.Controls.Converters;assembly=Avalonia.Controls"
+    xmlns:converters="clr-namespace:Semi.Avalonia.Converters"
     x:CompileBindings="True">
 
     <Design.PreviewWith>
@@ -40,8 +40,8 @@
                         AllowAutoHide="{TemplateBinding (ScrollViewer.AllowAutoHide)}"
                         Background="{TemplateBinding Background}"
                         HorizontalScrollBarVisibility="{TemplateBinding (ScrollViewer.HorizontalScrollBarVisibility)}"
-                        IsScrollChainingEnabled="{TemplateBinding (ScrollViewer.IsScrollChainingEnabled)}"
                         IsDeferredScrollingEnabled="{TemplateBinding (ScrollViewer.IsDeferredScrollingEnabled)}"
+                        IsScrollChainingEnabled="{TemplateBinding (ScrollViewer.IsScrollChainingEnabled)}"
                         VerticalScrollBarVisibility="{TemplateBinding (ScrollViewer.VerticalScrollBarVisibility)}">
                         <ItemsPresenter
                             Name="PART_ItemsPresenter"
@@ -52,11 +52,7 @@
             </ControlTemplate>
         </Setter>
     </ControlTheme>
-
-    <converters:MarginMultiplierConverter
-        x:Key="TreeViewItemLeftMarginConverter"
-        Indent="{StaticResource TreeViewItemIndent}"
-        Left="True" />
+    
     <ControlTheme x:Key="ToggleButtonTreeViewItemIconButton" TargetType="ToggleButton">
         <Setter Property="Margin" Value="0" />
         <Setter Property="Cursor" Value="Hand" />
@@ -71,10 +67,10 @@
                     Background="Transparent">
                     <PathIcon
                         Name="PART_ExpandIconPath"
-                        Theme="{StaticResource InnerPathIcon}"
                         Classes="Small"
                         Data="{DynamicResource ExpanderIconData}"
-                        Foreground="{DynamicResource TreeViewItemIconDefaultForeground}">
+                        Foreground="{DynamicResource TreeViewItemIconDefaultForeground}"
+                        Theme="{StaticResource InnerPathIcon}">
                         <PathIcon.Transitions>
                             <Transitions>
                                 <TransformOperationsTransition Property="RenderTransform" Duration="0.1" />
@@ -110,16 +106,20 @@
                         CornerRadius="{TemplateBinding CornerRadius}"
                         Focusable="True"
                         TemplatedControl.IsTemplateFocusTarget="True">
-                        <Grid
-                            Name="PART_Header"
-                            Margin="{TemplateBinding Level, Mode=OneWay, Converter={StaticResource TreeViewItemLeftMarginConverter}}"
-                            ColumnDefinitions="Auto, *">
+                        <Grid Name="PART_Header" ColumnDefinitions="Auto, *">
+                            <Grid.Margin>
+                                <MultiBinding Converter="{x:Static converters:TreeViewItemIndentConverter.Instance}">
+                                    <Binding Path="Level" RelativeSource="{RelativeSource TemplatedParent}" />
+                                    <DynamicResource ResourceKey="TreeViewItemIndent" />
+                                </MultiBinding>
+                            </Grid.Margin>
                             <ToggleButton
                                 Name="PART_ExpandCollapseChevron"
                                 Grid.Column="0"
                                 Padding="{DynamicResource TreeViewItemIconMargin}"
                                 Focusable="False"
-                                IsChecked="{TemplateBinding IsExpanded, Mode=TwoWay}"
+                                IsChecked="{TemplateBinding IsExpanded,
+                                                            Mode=TwoWay}"
                                 Theme="{StaticResource ToggleButtonTreeViewItemIconButton}" />
                             <ContentPresenter
                                 Name="PART_HeaderPresenter"
diff --git a/src/Semi.Avalonia/Converters/TreeViewItemIndentConverter.cs b/src/Semi.Avalonia/Converters/TreeViewItemIndentConverter.cs
new file mode 100644
index 0000000..b0a2e99
--- /dev/null
+++ b/src/Semi.Avalonia/Converters/TreeViewItemIndentConverter.cs
@@ -0,0 +1,25 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using Avalonia;
+using Avalonia.Data.Converters;
+
+namespace Semi.Avalonia.Converters;
+
+public class TreeViewItemIndentConverter: IMultiValueConverter
+{
+    public static TreeViewItemIndentConverter Instance = new();
+    
+    public object? Convert(IList<object?> values, Type targetType, object? parameter, CultureInfo culture)
+    {
+        if (values[0] is int level && values[1] is double indent)
+        {
+            return new Thickness( 
+                indent * level,
+                0,
+                0,
+                0);
+        }
+        return new Thickness(0);
+    }
+}
\ No newline at end of file