From 1bbff64d1fffd557c031e5fc4e78b003fdfe2c35 Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Fri, 8 Jul 2022 16:50:39 +0200
Subject: [PATCH] Added preview to TreeView ControlTheme.

---
 .../Controls/TreeView.xaml                    | 66 +++++++++++--------
 1 file changed, 39 insertions(+), 27 deletions(-)

diff --git a/src/Avalonia.Themes.Fluent/Controls/TreeView.xaml b/src/Avalonia.Themes.Fluent/Controls/TreeView.xaml
index 4fcec79f25..c340599000 100644
--- a/src/Avalonia.Themes.Fluent/Controls/TreeView.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/TreeView.xaml
@@ -1,31 +1,43 @@
 <ResourceDictionary xmlns="https://github.com/avaloniaui"
                     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+  <Design.PreviewWith>
+    <Border Padding="20">
+      <StackPanel Spacing="20">
+        <TreeView>
+          <TreeViewItem Header="Root" IsExpanded="True">
+            <TreeViewItem Header="Child1"/>
+            <TreeViewItem Header="Child2"/>
+          </TreeViewItem>
+        </TreeView>
+      </StackPanel>
+    </Border>
+  </Design.PreviewWith>
 
-    <ControlTheme x:Key="{x:Type TreeView}" TargetType="TreeView">
-      <Setter Property="Background" Value="Transparent" />
-      <Setter Property="BorderBrush" Value="Transparent" />
-      <Setter Property="BorderThickness" Value="0" />
-      <Setter Property="Padding" Value="0" />
-      <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto" />
-      <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto" />
-      <Setter Property="ScrollViewer.IsScrollChainingEnabled" Value="True" />
-      <Setter Property="Template">
-        <ControlTemplate>
-          <Border BorderBrush="{TemplateBinding BorderBrush}"
-                  BorderThickness="{TemplateBinding BorderThickness}"
-                  CornerRadius="{TemplateBinding CornerRadius}">
-            <ScrollViewer Background="{TemplateBinding Background}"
-                          HorizontalScrollBarVisibility="{TemplateBinding (ScrollViewer.HorizontalScrollBarVisibility)}"
-                          VerticalScrollBarVisibility="{TemplateBinding (ScrollViewer.VerticalScrollBarVisibility)}"
-                          IsScrollChainingEnabled="{TemplateBinding (ScrollViewer.IsScrollChainingEnabled)}"
-                          AllowAutoHide="{TemplateBinding (ScrollViewer.AllowAutoHide)}">
-              <ItemsPresenter Name="PART_ItemsPresenter"
-                              Items="{TemplateBinding Items}"
-                              ItemsPanel="{TemplateBinding ItemsPanel}"
-                              Margin="{TemplateBinding Padding}" />
-            </ScrollViewer>
-          </Border>
-        </ControlTemplate>
-      </Setter>
-    </ControlTheme>
+  <ControlTheme x:Key="{x:Type TreeView}" TargetType="TreeView">
+    <Setter Property="Background" Value="Transparent" />
+    <Setter Property="BorderBrush" Value="Transparent" />
+    <Setter Property="BorderThickness" Value="0" />
+    <Setter Property="Padding" Value="0" />
+    <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto" />
+    <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto" />
+    <Setter Property="ScrollViewer.IsScrollChainingEnabled" Value="True" />
+    <Setter Property="Template">
+      <ControlTemplate>
+        <Border BorderBrush="{TemplateBinding BorderBrush}"
+                BorderThickness="{TemplateBinding BorderThickness}"
+                CornerRadius="{TemplateBinding CornerRadius}">
+          <ScrollViewer Background="{TemplateBinding Background}"
+                        HorizontalScrollBarVisibility="{TemplateBinding (ScrollViewer.HorizontalScrollBarVisibility)}"
+                        VerticalScrollBarVisibility="{TemplateBinding (ScrollViewer.VerticalScrollBarVisibility)}"
+                        IsScrollChainingEnabled="{TemplateBinding (ScrollViewer.IsScrollChainingEnabled)}"
+                        AllowAutoHide="{TemplateBinding (ScrollViewer.AllowAutoHide)}">
+            <ItemsPresenter Name="PART_ItemsPresenter"
+                            Items="{TemplateBinding Items}"
+                            ItemsPanel="{TemplateBinding ItemsPanel}"
+                            Margin="{TemplateBinding Padding}" />
+          </ScrollViewer>
+        </Border>
+      </ControlTemplate>
+    </Setter>
+  </ControlTheme>
 </ResourceDictionary>