From 55f8b5104e5d45811e7f0f84a1694f8ac23fde3e Mon Sep 17 00:00:00 2001
From: Yimeng Wu <me@kinnara.cn>
Date: Mon, 15 Jun 2020 00:34:18 +0800
Subject: [PATCH] Remove the need to set an explicit style for a ListView that
 uses GridView (#114)

---
 .../ControlPages/ListViewPage.xaml            |  3 +-
 .../Primitives/IsGridViewConverter.cs         | 19 +++++
 ModernWpf/Styles/ListView.xaml                | 71 +++++++++++--------
 3 files changed, 61 insertions(+), 32 deletions(-)
 create mode 100644 ModernWpf/Controls/Primitives/IsGridViewConverter.cs

diff --git a/ModernWpf.SampleApp/ControlPages/ListViewPage.xaml b/ModernWpf.SampleApp/ControlPages/ListViewPage.xaml
index 25b8fd32..85ec8569 100644
--- a/ModernWpf.SampleApp/ControlPages/ListViewPage.xaml
+++ b/ModernWpf.SampleApp/ControlPages/ListViewPage.xaml
@@ -134,10 +134,9 @@
         </TabItem>
 
         <TabItem Header="GridView">
-            <sc:ControlExample HeaderText="A ListView with a GridView as the view mode">
+            <sc:ControlExample HeaderText="A ListView that uses a GridView view mode">
                 <ListView
                     x:Name="listView3"
-                    Style="{StaticResource {x:Static GridView.GridViewStyleKey}}"
                     ItemsSource="{Binding}"
                     VirtualizingPanel.VirtualizationMode="Recycling">
                     <ListView.View>
diff --git a/ModernWpf/Controls/Primitives/IsGridViewConverter.cs b/ModernWpf/Controls/Primitives/IsGridViewConverter.cs
new file mode 100644
index 00000000..b5919c73
--- /dev/null
+++ b/ModernWpf/Controls/Primitives/IsGridViewConverter.cs
@@ -0,0 +1,19 @@
+using System;
+using System.Globalization;
+using System.Windows.Data;
+
+namespace ModernWpf.Controls.Primitives
+{
+    public class IsGridViewConverter : IValueConverter
+    {
+        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            return value is System.Windows.Controls.GridView;
+        }
+
+        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}
diff --git a/ModernWpf/Styles/ListView.xaml b/ModernWpf/Styles/ListView.xaml
index cdf66491..8573e64d 100644
--- a/ModernWpf/Styles/ListView.xaml
+++ b/ModernWpf/Styles/ListView.xaml
@@ -65,7 +65,33 @@
 
     <Style TargetType="ListViewItem" BasedOn="{StaticResource DefaultListViewItemStyle}" />
 
-    <Style x:Key="DefaultListViewStyle" TargetType="ListView">
+    <ControlTemplate x:Key="GridViewTemplate" TargetType="ListView">
+        <Border
+            x:Name="Bd"
+            BorderThickness="{TemplateBinding BorderThickness}"
+            Background="{TemplateBinding Background}"
+            BorderBrush="{TemplateBinding BorderBrush}"
+            SnapsToDevicePixels="true">
+            <local:ScrollViewerEx
+                Style="{DynamicResource {x:Static GridView.GridViewScrollViewerStyleKey}}"
+                Focusable="false"
+                Padding="{TemplateBinding Padding}"
+                primitives:ScrollViewerHelper.AutoHideScrollBars="{TemplateBinding primitives:ScrollViewerHelper.AutoHideScrollBars}">
+                <ItemsPresenter SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+            </local:ScrollViewerEx>
+        </Border>
+        <ControlTemplate.Triggers>
+            <MultiTrigger>
+                <MultiTrigger.Conditions>
+                    <Condition Property="IsGrouping" Value="true" />
+                    <Condition Property="VirtualizingPanel.IsVirtualizingWhenGrouping" Value="false" />
+                </MultiTrigger.Conditions>
+                <Setter Property="ScrollViewer.CanContentScroll" Value="false" />
+            </MultiTrigger>
+        </ControlTemplate.Triggers>
+    </ControlTemplate>
+
+    <Style x:Key="BaseListViewStyle" TargetType="ListView">
         <Setter Property="OverridesDefaultStyle" Value="True" />
         <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto" />
         <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto" />
@@ -105,6 +131,18 @@
         </Setter>
     </Style>
 
+    <Style x:Key="DefaultListViewStyle" TargetType="ListView" BasedOn="{StaticResource BaseListViewStyle}">
+        <Style.Resources>
+            <primitives:IsGridViewConverter x:Key="IsGridViewConverter" />
+        </Style.Resources>
+        <Style.Triggers>
+            <DataTrigger Binding="{Binding View, RelativeSource={RelativeSource Self}, Converter={StaticResource IsGridViewConverter}}" Value="True">
+                <Setter Property="Template" Value="{StaticResource GridViewTemplate}" />
+                <Setter Property="ItemContainerStyle" Value="{DynamicResource {x:Static GridView.GridViewItemContainerStyleKey}}" />
+            </DataTrigger>
+        </Style.Triggers>
+    </Style>
+
     <Style TargetType="ListView" BasedOn="{StaticResource DefaultListViewStyle}" />
 
     <!-- GridView ScrollViewer Style -->
@@ -353,36 +391,9 @@
         </Setter>
     </Style>
 
-    <Style x:Key="{x:Static GridView.GridViewStyleKey}" TargetType="ListView" BasedOn="{StaticResource DefaultListViewStyle}">
+    <Style x:Key="{x:Static GridView.GridViewStyleKey}" TargetType="ListView" BasedOn="{StaticResource BaseListViewStyle}">
         <Setter Property="ItemContainerStyle" Value="{DynamicResource {x:Static GridView.GridViewItemContainerStyleKey}}" />
-        <Setter Property="Template">
-            <Setter.Value>
-                <ControlTemplate TargetType="ListView">
-                    <Border
-                        x:Name="Bd"
-                        BorderThickness="{TemplateBinding BorderThickness}"
-                        Background="{TemplateBinding Background}"
-                        BorderBrush="{TemplateBinding BorderBrush}"
-                        SnapsToDevicePixels="true">
-                        <local:ScrollViewerEx
-                            Style="{DynamicResource {x:Static GridView.GridViewScrollViewerStyleKey}}"
-                            Focusable="false"
-                            Padding="{TemplateBinding Padding}">
-                            <ItemsPresenter SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
-                        </local:ScrollViewerEx>
-                    </Border>
-                    <ControlTemplate.Triggers>
-                        <MultiTrigger>
-                            <MultiTrigger.Conditions>
-                                <Condition Property="IsGrouping" Value="true" />
-                                <Condition Property="VirtualizingPanel.IsVirtualizingWhenGrouping" Value="false" />
-                            </MultiTrigger.Conditions>
-                            <Setter Property="ScrollViewer.CanContentScroll" Value="false" />
-                        </MultiTrigger>
-                    </ControlTemplate.Triggers>
-                </ControlTemplate>
-            </Setter.Value>
-        </Setter>
+        <Setter Property="Template" Value="{StaticResource GridViewTemplate}" />
     </Style>
 
 </ResourceDictionary>
\ No newline at end of file