pulled #15 and made some adjustments

HandyControl/Controls/Attach/DataGridAttach.cs

@@ -1,10 +1,8 @@
-using System;
-using System.Collections.Generic;
 using System.Linq;
 using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Controls.Primitives;
-using System.Windows.Media;
+using HandyControl.Data;
 
 namespace HandyControl.Controls
 {
@@ -211,72 +209,66 @@ namespace HandyControl.Controls
             }
         }
 
-        public static DependencyProperty ShowRowNumberProperty = DependencyProperty.RegisterAttached("ShowRowNumber", typeof(bool), typeof(DataGridAttach), new FrameworkPropertyMetadata(false, OnShowRowNumberChanged));
+        public static DependencyProperty ShowRowNumberProperty = DependencyProperty.RegisterAttached("ShowRowNumber",
+            typeof(bool), typeof(DataGridAttach),
+            new FrameworkPropertyMetadata(ValueBoxes.FalseBox, FrameworkPropertyMetadataOptions.Inherits, OnShowRowNumberChanged));
 
-        public static bool GetShowRowNumber(DependencyObject target)
-        {
-            return (bool)target.GetValue(ShowRowNumberProperty);
-        }
+        public static bool GetShowRowNumber(DependencyObject target) => (bool)target.GetValue(ShowRowNumberProperty);
 
-        public static void SetShowRowNumber(DependencyObject target, bool value)
-        {
-            target.SetValue(ShowRowNumberProperty, value);
-        }
+        public static void SetShowRowNumber(DependencyObject target, bool value) => target.SetValue(ShowRowNumberProperty, value);
 
         private static void OnShowRowNumberChanged(DependencyObject target, DependencyPropertyChangedEventArgs e)
         {
-            DataGrid dataGrid = target as DataGrid;
-            if ((bool)e.NewValue == true)
-            {
-                EventHandler<DataGridRowEventArgs> loadedRowHandler = null;
-                loadedRowHandler = (object sender, DataGridRowEventArgs ea) =>
-                {
-                    if (GetShowRowNumber(dataGrid) == false)
-                    {
-                        dataGrid.LoadingRow -= loadedRowHandler;
-                        return;
-                    }
-                    ea.Row.Header = ea.Row.GetIndex() + 1;
-                };
-                dataGrid.LoadingRow += loadedRowHandler;
+            if (!(target is DataGrid dataGrid)) return;
+            var show = (bool)e.NewValue;
 
-                ItemsChangedEventHandler itemsChangedHandler = null;
-                itemsChangedHandler = (object sender, ItemsChangedEventArgs ea) =>
-                {
-                    if (GetShowRowNumber(dataGrid) == false)
-                    {
-                        dataGrid.ItemContainerGenerator.ItemsChanged -= itemsChangedHandler;
-                        return;
-                    }
-                    GetVisualChildCollection<DataGridRow>(dataGrid).
-                        ForEach(d => d.Header = d.GetIndex());
-                };
-                dataGrid.ItemContainerGenerator.ItemsChanged += itemsChangedHandler;
+            if (show)
+            {
+                dataGrid.LoadingRow += DataGrid_LoadingRow;
+                dataGrid.ItemContainerGenerator.ItemsChanged += ItemContainerGenerator_ItemsChanged;
             }
-        }
-
-        private static List<T> GetVisualChildCollection<T>(object parent) where T : Visual
-        {
-            List<T> visualCollection = new List<T>();
-            GetVisualChildCollection(parent as DependencyObject, visualCollection);
-            return visualCollection;
-        }
-
-        private static void GetVisualChildCollection<T>(DependencyObject parent, List<T> visualCollection) where T : Visual
-        {
-            int count = VisualTreeHelper.GetChildrenCount(parent);
-            for (int i = 0; i < count; i++)
+            else
             {
-                DependencyObject child = VisualTreeHelper.GetChild(parent, i);
-                if (child is T)
+                dataGrid.LoadingRow -= DataGrid_LoadingRow;
+                dataGrid.ItemContainerGenerator.ItemsChanged -= ItemContainerGenerator_ItemsChanged;
+            }
+
+            UpdateItems(dataGrid.ItemContainerGenerator, show);
+        }
+
+        private static void ItemContainerGenerator_ItemsChanged(object sender, ItemsChangedEventArgs e)
+        {
+            if (!(sender is ItemContainerGenerator generator)) return;
+            UpdateItems(generator);
+        }
+
+        private static void UpdateItems(ItemContainerGenerator generator, bool show = true)
+        {
+            var count = generator.Items.Count;
+            if (show)
+            {
+                for (int i = 0; i < count; i++)
                 {
-                    visualCollection.Add(child as T);
+                    var row = (DataGridRow)generator.ContainerFromIndex(i);
+                    if (row != null)
+                    {
+                        row.Header = (i + 1).ToString();
+                    }
                 }
-                if (child != null)
+            }
+            else
+            {
+                for (int i = 0; i < count; i++)
                 {
-                    GetVisualChildCollection(child, visualCollection);
+                    var row = (DataGridRow)generator.ContainerFromIndex(i);
+                    if (row != null)
+                    {
+                        row.Header = null;
+                    }
                 }
             }
         }
+
+        private static void DataGrid_LoadingRow(object sender, DataGridRowEventArgs e) => e.Row.Header = (e.Row.GetIndex() + 1).ToString();
     }
 }

HandyControl/Controls/TransitioningContentControl.cs

@@ -119,7 +119,7 @@ namespace HandyControl.Controls
 
         private Storyboard GetStoryboard(string newTransition)
         {
-            var presentationGroup = VisualStates.TryGetVisualStateGroup(this, PresentationGroup);
+            var presentationGroup = VisualHelper.TryGetVisualStateGroup(this, PresentationGroup);
             Storyboard newStoryboard = null;
             if (presentationGroup != null)
                 newStoryboard = presentationGroup.States
@@ -218,7 +218,7 @@ namespace HandyControl.Controls
             var newStoryboard = source.GetStoryboard(newTransition);
 
             if (newStoryboard == null)
-                if (VisualStates.TryGetVisualStateGroup(source, PresentationGroup) == null)
+                if (VisualHelper.TryGetVisualStateGroup(source, PresentationGroup) == null)
                 {
                     source.CurrentTransition = null;
                 }

HandyControl/HandyControl.csproj

@@ -204,7 +204,7 @@
     <Compile Include="Tools\RegularPatterns.cs" />
     <Compile Include="Tools\ResourceHelper.cs" />
     <Compile Include="Tools\ValidateHelper.cs" />
-    <Compile Include="Tools\VisualStates.cs" />
+    <Compile Include="Tools\VisualHelper.cs" />
   </ItemGroup>
   <ItemGroup>
     <Page Include="Themes\Basic\Basic.xaml">

HandyControl/Themes/Styles/DataGrid.xaml

@@ -82,14 +82,15 @@
                         <DataGridDetailsPresenter Margin="0,6" Grid.Column="1" Grid.Row="1" SelectiveScrollingGrid.SelectiveScrollingOrientation="{Binding AreRowDetailsFrozen, ConverterParameter={x:Static SelectiveScrollingOrientation.Vertical}, Converter={x:Static DataGrid.RowDetailsScrollingConverter}, RelativeSource={RelativeSource AncestorType={x:Type DataGrid}}}" Visibility="{TemplateBinding DetailsVisibility}"/>
                         <DataGridRowHeader Grid.Row="0" Grid.Column="0" SelectiveScrollingGrid.SelectiveScrollingOrientation="Vertical" Visibility="{Binding HeadersVisibility, ConverterParameter={x:Static DataGridHeadersVisibility.Row}, Converter={x:Static DataGrid.HeadersVisibilityConverter}, RelativeSource={RelativeSource AncestorType={x:Type DataGrid}}}"/>
                     </SelectiveScrollingGrid>
-                    <ControlTemplate.Triggers>
-                        <Trigger Property="IsSelected" Value="True">
-                            <Setter Property="Background" Value="{DynamicResource PrimaryBrush}"/>
-                        </Trigger>
-                    </ControlTemplate.Triggers>
                 </ControlTemplate>
             </Setter.Value>
         </Setter>
+        <Style.Triggers>
+            <Trigger Property="IsSelected" Value="True">
+                <Setter Property="Background" Value="{DynamicResource PrimaryBrush}"/>
+                <Setter Property="TextElement.Foreground" Value="White"/>
+            </Trigger>
+        </Style.Triggers>
     </Style>
     <Style x:Key="ColumnHeaderGripperStyle" TargetType="Thumb">
         <Setter Property="Width" Value="8"/>

HandyControl/Tools/VisualHelper.cs

@@ -4,7 +4,7 @@ using System.Windows.Media;
 
 namespace HandyControl.Tools
 {
-    public class VisualStates
+    internal class VisualHelper
     {
         public static VisualStateGroup TryGetVisualStateGroup(DependencyObject dependencyObject, string groupName)
         {

HandyControlDemo/UserControl/Styles/DataGridDemoCtl.xaml

@@ -6,26 +6,47 @@
              xmlns:langs="clr-namespace:HandyControlDemo.Properties.Langs"
              xmlns:controls="clr-namespace:HandyControl.Controls;assembly=HandyControl">
     <controls:TransitioningContentControl>
-        <DataGrid HeadersVisibility="All" RowHeaderWidth="60" AutoGenerateColumns="False" ItemsSource="{Binding DataList}">
-            <DataGrid.RowHeaderTemplate>
-                <DataTemplate>
-                    <CheckBox IsChecked="{Binding IsSelected,RelativeSource={RelativeSource FindAncestor,AncestorType=DataGridRow}}"/>
-                </DataTemplate>
-            </DataGrid.RowHeaderTemplate>
-            <DataGrid.Columns>
-                <DataGridTextColumn IsReadOnly="True" Width="80" CanUserResize="False" Binding="{Binding Index}" Header="{x:Static langs:Lang.Index}"/>
-                <DataGridTemplateColumn Width="50" CanUserResize="False">
-                    <DataGridTemplateColumn.CellTemplate>
+        <TabControl Style="{StaticResource TabControlInLine}">
+            <TabItem Header="Common">
+                <DataGrid HeadersVisibility="All" RowHeaderWidth="60" AutoGenerateColumns="False" ItemsSource="{Binding DataList}">
+                    <DataGrid.RowHeaderTemplate>
                         <DataTemplate>
-                            <Image Source="{Binding ImgPath}" Width="32" Height="32" Stretch="Uniform"/>
+                            <CheckBox IsChecked="{Binding IsSelected,RelativeSource={RelativeSource FindAncestor,AncestorType=DataGridRow}}"/>
                         </DataTemplate>
-                    </DataGridTemplateColumn.CellTemplate>
-                </DataGridTemplateColumn>
-                <DataGridTextColumn Width="1*" Binding="{Binding Name}" Header="{x:Static langs:Lang.Name}"/>
-                <DataGridCheckBoxColumn Width="100" CanUserResize="False" Binding="{Binding IsSelected}" Header="{x:Static langs:Lang.Selected}"/>
-                <DataGridComboBoxColumn ItemsSource="{Binding Source={StaticResource DemoTypes}}" Width="100" CanUserResize="False" SelectedValueBinding="{Binding Type}" Header="{x:Static langs:Lang.Type}"/>
-                <DataGridTextColumn Width="1*" Binding="{Binding Remark}" Header="{x:Static langs:Lang.Remark}"/>
-            </DataGrid.Columns>
-        </DataGrid>
+                    </DataGrid.RowHeaderTemplate>
+                    <DataGrid.Columns>
+                        <DataGridTextColumn IsReadOnly="True" Width="80" CanUserResize="False" Binding="{Binding Index}" Header="{x:Static langs:Lang.Index}"/>
+                        <DataGridTemplateColumn Width="50" CanUserResize="False">
+                            <DataGridTemplateColumn.CellTemplate>
+                                <DataTemplate>
+                                    <Image Source="{Binding ImgPath}" Width="32" Height="32" Stretch="Uniform"/>
+                                </DataTemplate>
+                            </DataGridTemplateColumn.CellTemplate>
+                        </DataGridTemplateColumn>
+                        <DataGridTextColumn Width="1*" Binding="{Binding Name}" Header="{x:Static langs:Lang.Name}"/>
+                        <DataGridCheckBoxColumn Width="100" CanUserResize="False" Binding="{Binding IsSelected}" Header="{x:Static langs:Lang.Selected}"/>
+                        <DataGridComboBoxColumn ItemsSource="{Binding Source={StaticResource DemoTypes}}" Width="100" CanUserResize="False" SelectedValueBinding="{Binding Type}" Header="{x:Static langs:Lang.Type}"/>
+                        <DataGridTextColumn Width="1*" Binding="{Binding Remark}" Header="{x:Static langs:Lang.Remark}"/>
+                    </DataGrid.Columns>
+                </DataGrid>
+            </TabItem>
+            <TabItem Header="ShowRowNumber">
+                <DataGrid HeadersVisibility="All" RowHeaderWidth="60" AutoGenerateColumns="False" ItemsSource="{Binding DataList}" controls:DataGridAttach.ShowRowNumber="True">
+                    <DataGrid.Columns>
+                        <DataGridTemplateColumn Width="50" CanUserResize="False">
+                            <DataGridTemplateColumn.CellTemplate>
+                                <DataTemplate>
+                                    <Image Source="{Binding ImgPath}" Width="32" Height="32" Stretch="Uniform"/>
+                                </DataTemplate>
+                            </DataGridTemplateColumn.CellTemplate>
+                        </DataGridTemplateColumn>
+                        <DataGridTextColumn Width="1*" Binding="{Binding Name}" Header="{x:Static langs:Lang.Name}"/>
+                        <DataGridCheckBoxColumn Width="100" CanUserResize="False" Binding="{Binding IsSelected}" Header="{x:Static langs:Lang.Selected}"/>
+                        <DataGridComboBoxColumn ItemsSource="{Binding Source={StaticResource DemoTypes}}" Width="100" CanUserResize="False" SelectedValueBinding="{Binding Type}" Header="{x:Static langs:Lang.Type}"/>
+                        <DataGridTextColumn Width="1*" Binding="{Binding Remark}" Header="{x:Static langs:Lang.Remark}"/>
+                    </DataGrid.Columns>
+                </DataGrid>
+            </TabItem>
+        </TabControl>
     </controls:TransitioningContentControl>
 </UserControl>