From 3831237c41ff533b1dc2fcbe0a587915b19d5f02 Mon Sep 17 00:00:00 2001
From: SKProCH <skproch@yandex.ru>
Date: Sat, 9 May 2026 03:42:45 +0300
Subject: [PATCH] Fixes DataGrid ScrollBars with Auto

Fix #512
---
 Material.Avalonia.DataGrid/DataGrid.axaml | 25 +++++++++++++++--------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/Material.Avalonia.DataGrid/DataGrid.axaml b/Material.Avalonia.DataGrid/DataGrid.axaml
index 14f2e5d5..ff10d2b8 100644
--- a/Material.Avalonia.DataGrid/DataGrid.axaml
+++ b/Material.Avalonia.DataGrid/DataGrid.axaml
@@ -3,7 +3,7 @@
                     xmlns:ripple="clr-namespace:Material.Ripple;assembly=Material.Ripple"
                     xmlns:collections="clr-namespace:Avalonia.Collections;assembly=Avalonia.Controls.DataGrid">
   <!--TODO: Validation and Focus-->
-  
+
   <Thickness x:Key="DataGridTextColumnCellTextBlockMargin">0</Thickness>
 
   <ControlTheme x:Key="DataGridCellTextBlockTheme" TargetType="TextBlock">
@@ -264,7 +264,7 @@
                 BorderThickness="{TemplateBinding BorderThickness}"
                 BorderBrush="{TemplateBinding BorderBrush}"
                 CornerRadius="4">
-          <Grid RowDefinitions="Auto,*,Auto,Auto" ColumnDefinitions="Auto,*,Auto">
+          <Grid RowDefinitions="Auto,*,Auto" ColumnDefinitions="Auto,*,Auto">
 
             <DataGridColumnHeader Name="PART_TopLeftCornerHeader" Width="22" />
             <DataGridColumnHeadersPresenter Name="PART_ColumnHeadersPresenter" Grid.Column="1" />
@@ -273,26 +273,33 @@
                        VerticalAlignment="Bottom" Height="1"
                        Background="{TemplateBinding BorderBrush}" />
 
-            <DataGridRowsPresenter Name="PART_RowsPresenter" Grid.ColumnSpan="2" Grid.Row="1">
+            <DataGridRowsPresenter Name="PART_RowsPresenter" Grid.Row="1"
+                                   ScrollViewer.IsScrollInertiaEnabled="{TemplateBinding IsScrollInertiaEnabled}">
               <DataGridRowsPresenter.GestureRecognizers>
-                <ScrollGestureRecognizer CanHorizontallyScroll="True" CanVerticallyScroll="True" />
+                <ScrollGestureRecognizer CanHorizontallyScroll="True" CanVerticallyScroll="True"
+                                         IsScrollInertiaEnabled="{Binding (ScrollViewer.IsScrollInertiaEnabled), ElementName=PART_RowsPresenter}" />
               </DataGridRowsPresenter.GestureRecognizers>
             </DataGridRowsPresenter>
             <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" Classes="Modern"
-                       Orientation="Vertical" Grid.Column="2" Grid.Row="1" />
+            <ScrollBar Name="PART_VerticalScrollbar" Orientation="Vertical" 
+                       Grid.Column="2" Grid.Row="1" />
 
             <Grid Grid.Column="1" Grid.Row="2"
                   ColumnDefinitions="Auto,*">
               <Rectangle Name="PART_FrozenColumnScrollBarSpacer" />
-              <ScrollBar Name="PART_HorizontalScrollbar" Grid.Column="1"
-                         Classes="Modern" Orientation="Horizontal" />
+              <ScrollBar Name="PART_HorizontalScrollbar" Orientation="Horizontal"
+                         Grid.Column="1"/>
             </Grid>
           </Grid>
         </Border>
       </ControlTemplate>
     </Setter>
+    
+    <Style Selector="^ /template/ DataGridRowsPresenter#PART_RowsPresenter">
+      <Setter Property="Grid.RowSpan" Value="2" />
+      <Setter Property="Grid.ColumnSpan" Value="3" />
+    </Style>
 
     <Style Selector="^ /template/ ScrollBar">
       <Setter Property="Theme" Value="{StaticResource MaterialModernScrollBar}" />
@@ -309,7 +316,7 @@
         <Setter Property="Height" Value="{DynamicResource ScrollBarThickness}" />
       </Style>
       <Style Selector="^:vertical">
-        <Setter Property="Height" Value="{DynamicResource ScrollBarThickness}" />
+        <Setter Property="Width" Value="{DynamicResource ScrollBarThickness}" />
       </Style>
     </Style>
   </ControlTheme>