From 55709f7ffa50c8fd0334dcba6cd733288eee5998 Mon Sep 17 00:00:00 2001
From: Edward Miller <symbiogenisis@outlook.com>
Date: Tue, 16 Jan 2024 16:28:51 -0600
Subject: [PATCH] support multiple selection

---
 Maui.DataGrid.Sample/MainPage.xaml            |   2 +-
 .../Maui.DataGrid.Sample.csproj               |   6 +-
 .../Platforms/Windows/App.xaml                |   8 +-
 Maui.DataGrid.Sample/SettingsPopup.xaml       |   4 +-
 .../ViewModels/MainViewModel.cs               |   8 +-
 Maui.DataGrid/BoolToSelectionModeConverter.cs |  21 ---
 Maui.DataGrid/CompatibilitySuppressions.xml   | 113 ++++++++++++-
 Maui.DataGrid/DataGrid.xaml                   |   8 +-
 Maui.DataGrid/DataGrid.xaml.cs                | 148 ++++++++++++++++--
 Maui.DataGrid/DataGridRow.cs                  |   8 +-
 10 files changed, 278 insertions(+), 48 deletions(-)
 delete mode 100644 Maui.DataGrid/BoolToSelectionModeConverter.cs

diff --git a/Maui.DataGrid.Sample/MainPage.xaml b/Maui.DataGrid.Sample/MainPage.xaml
index 0ebb702..289cf47 100644
--- a/Maui.DataGrid.Sample/MainPage.xaml
+++ b/Maui.DataGrid.Sample/MainPage.xaml
@@ -14,7 +14,7 @@
             <Button Text="Settings" WidthRequest="100" Clicked="OnSettingsClicked" />
         </Grid>
 
-        <dg:DataGrid Grid.Row="1" ItemsSource="{Binding Teams}" SelectionEnabled="{Binding SelectionEnabled}" SelectedItem="{Binding SelectedTeam}"
+        <dg:DataGrid Grid.Row="1" ItemsSource="{Binding Teams}" SelectionMode="{Binding SelectionMode}" SelectedItem="{Binding SelectedTeam}"
                      RowHeight="70" HeaderHeight="50" BorderColor="{StaticResource GridBorderColor}" RowToEdit="{Binding TeamToEdit}"
                      HeaderBackground="{StaticResource GridHeaderBgColor}" HeaderBordersVisible="{Binding HeaderBordersVisible}"
                      PullToRefreshCommand="{Binding Commands[Refresh]}" IsRefreshing="{Binding IsRefreshing}"
diff --git a/Maui.DataGrid.Sample/Maui.DataGrid.Sample.csproj b/Maui.DataGrid.Sample/Maui.DataGrid.Sample.csproj
index 898b3e2..82a64d0 100644
--- a/Maui.DataGrid.Sample/Maui.DataGrid.Sample.csproj
+++ b/Maui.DataGrid.Sample/Maui.DataGrid.Sample.csproj
@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
 	<PropertyGroup>
 		<TargetFrameworks>net8.0-android;net8.0-ios;net8.0-maccatalyst</TargetFrameworks>
@@ -74,6 +74,10 @@
 	  <EmbeddedResource Include="teams.json" />
 	</ItemGroup>
 
+	<ItemGroup>
+	  <None Include="..\.editorconfig" Link=".editorconfig" />
+	</ItemGroup>
+
 	<ItemGroup>
 	  <ProjectReference Include="..\Maui.DataGrid\Maui.DataGrid.csproj" />
 	</ItemGroup>
diff --git a/Maui.DataGrid.Sample/Platforms/Windows/App.xaml b/Maui.DataGrid.Sample/Platforms/Windows/App.xaml
index e9ad3fb..537b3da 100644
--- a/Maui.DataGrid.Sample/Platforms/Windows/App.xaml
+++ b/Maui.DataGrid.Sample/Platforms/Windows/App.xaml
@@ -1,8 +1,14 @@
-<maui:MauiWinUIApplication
+<maui:MauiWinUIApplication
     x:Class="Maui.DataGrid.Sample.WinUI.App"
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
     xmlns:maui="using:Microsoft.Maui"
     xmlns:local="using:Maui.DataGrid.Sample.WinUI">
 
+    <maui:MauiWinUIApplication.Resources>
+        <StaticResource x:Key="ListViewItemCheckBrush" ResourceKey="ControlAltFillColorTransparent" />
+        <StaticResource x:Key="ListViewItemCheckBoxBrush" ResourceKey="ControlAltFillColorTransparent" />
+        <ListViewItemPresenterCheckMode x:Key="ListViewItemCheckMode">Overlay</ListViewItemPresenterCheckMode>
+    </maui:MauiWinUIApplication.Resources>
+
 </maui:MauiWinUIApplication>
diff --git a/Maui.DataGrid.Sample/SettingsPopup.xaml b/Maui.DataGrid.Sample/SettingsPopup.xaml
index f2ec052..085ad79 100644
--- a/Maui.DataGrid.Sample/SettingsPopup.xaml
+++ b/Maui.DataGrid.Sample/SettingsPopup.xaml
@@ -34,8 +34,8 @@
                     <Label Text="Pagination Enabled?" TextColor="White" VerticalOptions="Center" />
                 </HorizontalStackLayout>
                 <HorizontalStackLayout Style="{StaticResource SampleContainerStyle}">
-                    <CheckBox IsChecked="{Binding SelectionEnabled}" />
-                    <Label Text="Selection Enabled?" TextColor="White" VerticalOptions="Center" />
+                    <Picker SelectedItem="{Binding SelectionMode}" ItemsSource="{Binding SelectionModes}" />
+                    <Label Text="Selection Mode" TextColor="White" VerticalOptions="Center" />
                 </HorizontalStackLayout>
                 <HorizontalStackLayout Style="{StaticResource SampleContainerStyle}">
                     <Stepper Minimum="0" Maximum="200" Increment="10" Value="{Binding TeamColumnWidth}"
diff --git a/Maui.DataGrid.Sample/ViewModels/MainViewModel.cs b/Maui.DataGrid.Sample/ViewModels/MainViewModel.cs
index 82a7b8b..f7f6ccd 100644
--- a/Maui.DataGrid.Sample/ViewModels/MainViewModel.cs
+++ b/Maui.DataGrid.Sample/ViewModels/MainViewModel.cs
@@ -13,8 +13,8 @@ public MainViewModel()
         WonColumnVisible = true;
         HeaderBordersVisible = true;
         PaginationEnabled = true;
-        SelectionEnabled = true;
         TeamColumnWidth = 70;
+        SelectionMode = SelectionMode.Single;
         PageSize = 6;
 
         Commands.Add("CompleteEdit", new Command(CmdCompleteEdit));
@@ -22,6 +22,8 @@ public MainViewModel()
         Commands.Add("Refresh", new Command(CmdRefresh));
     }
 
+    public IEnumerable<SelectionMode> SelectionModes => Enum.GetValues<SelectionMode>().Cast<SelectionMode>();
+
     public ObservableCollection<DataGridColumn> Columns { get; set; }
 
     public Team TeamToEdit
@@ -72,9 +74,9 @@ public bool PaginationEnabled
         set => SetValue(value);
     }
 
-    public bool SelectionEnabled
+    public SelectionMode SelectionMode
     {
-        get => GetValue<bool>();
+        get => GetValue<SelectionMode>();
         set => SetValue(value);
     }
 
diff --git a/Maui.DataGrid/BoolToSelectionModeConverter.cs b/Maui.DataGrid/BoolToSelectionModeConverter.cs
deleted file mode 100644
index bb631b4..0000000
--- a/Maui.DataGrid/BoolToSelectionModeConverter.cs
+++ /dev/null
@@ -1,21 +0,0 @@
-namespace Maui.DataGrid;
-
-using System.Globalization;
-
-internal sealed class BoolToSelectionModeConverter : IValueConverter
-{
-    public object Convert(object? value, Type targetType, object? parameter, CultureInfo culture)
-    {
-        return value is true ? SelectionMode.Single : SelectionMode.None;
-    }
-
-    public object ConvertBack(object? value, Type targetType, object? parameter, CultureInfo culture)
-    {
-        if (value is not SelectionMode selectionMode)
-        {
-            throw new InvalidDataException("Converter can only process SelectionMode enums");
-        }
-
-        return selectionMode == SelectionMode.Single;
-    }
-}
diff --git a/Maui.DataGrid/CompatibilitySuppressions.xml b/Maui.DataGrid/CompatibilitySuppressions.xml
index f91f65d..e88c2bf 100644
--- a/Maui.DataGrid/CompatibilitySuppressions.xml
+++ b/Maui.DataGrid/CompatibilitySuppressions.xml
@@ -1,5 +1,116 @@
 <?xml version="1.0" encoding="utf-8"?>
 <!-- https://learn.microsoft.com/en-us/dotnet/fundamentals/package-validation/diagnostic-ids -->
 <Suppressions xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
-
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>F:Maui.DataGrid.DataGrid.SelectedItemsProperty</Target>
+    <Left>lib/net7.0/Maui.DataGrid.dll</Left>
+    <Right>lib/net7.0/Maui.DataGrid.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>F:Maui.DataGrid.DataGrid.SelectionModeProperty</Target>
+    <Left>lib/net7.0/Maui.DataGrid.dll</Left>
+    <Right>lib/net7.0/Maui.DataGrid.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Maui.DataGrid.DataGrid.get_SelectedItems</Target>
+    <Left>lib/net7.0/Maui.DataGrid.dll</Left>
+    <Right>lib/net7.0/Maui.DataGrid.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Maui.DataGrid.DataGrid.get_SelectionEnabled</Target>
+    <Left>lib/net7.0/Maui.DataGrid.dll</Left>
+    <Right>lib/net7.0/Maui.DataGrid.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Maui.DataGrid.DataGrid.get_SelectionMode</Target>
+    <Left>lib/net7.0/Maui.DataGrid.dll</Left>
+    <Right>lib/net7.0/Maui.DataGrid.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Maui.DataGrid.DataGrid.set_SelectedItems(System.Collections.ObjectModel.ObservableCollection{System.Object})</Target>
+    <Left>lib/net7.0/Maui.DataGrid.dll</Left>
+    <Right>lib/net7.0/Maui.DataGrid.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Maui.DataGrid.DataGrid.set_SelectionEnabled(System.Boolean)</Target>
+    <Left>lib/net7.0/Maui.DataGrid.dll</Left>
+    <Right>lib/net7.0/Maui.DataGrid.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Maui.DataGrid.DataGrid.set_SelectionMode(Microsoft.Maui.Controls.SelectionMode)</Target>
+    <Left>lib/net7.0/Maui.DataGrid.dll</Left>
+    <Right>lib/net7.0/Maui.DataGrid.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>F:Maui.DataGrid.DataGrid.SelectedItemsProperty</Target>
+    <Left>lib/net8.0/Maui.DataGrid.dll</Left>
+    <Right>lib/net8.0/Maui.DataGrid.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>F:Maui.DataGrid.DataGrid.SelectionModeProperty</Target>
+    <Left>lib/net8.0/Maui.DataGrid.dll</Left>
+    <Right>lib/net8.0/Maui.DataGrid.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Maui.DataGrid.DataGrid.get_SelectedItems</Target>
+    <Left>lib/net8.0/Maui.DataGrid.dll</Left>
+    <Right>lib/net8.0/Maui.DataGrid.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Maui.DataGrid.DataGrid.get_SelectionEnabled</Target>
+    <Left>lib/net8.0/Maui.DataGrid.dll</Left>
+    <Right>lib/net8.0/Maui.DataGrid.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Maui.DataGrid.DataGrid.get_SelectionMode</Target>
+    <Left>lib/net8.0/Maui.DataGrid.dll</Left>
+    <Right>lib/net8.0/Maui.DataGrid.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Maui.DataGrid.DataGrid.set_SelectedItems(System.Collections.ObjectModel.ObservableCollection{System.Object})</Target>
+    <Left>lib/net8.0/Maui.DataGrid.dll</Left>
+    <Right>lib/net8.0/Maui.DataGrid.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Maui.DataGrid.DataGrid.set_SelectionEnabled(System.Boolean)</Target>
+    <Left>lib/net8.0/Maui.DataGrid.dll</Left>
+    <Right>lib/net8.0/Maui.DataGrid.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Maui.DataGrid.DataGrid.set_SelectionMode(Microsoft.Maui.Controls.SelectionMode)</Target>
+    <Left>lib/net8.0/Maui.DataGrid.dll</Left>
+    <Right>lib/net8.0/Maui.DataGrid.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
 </Suppressions>
\ No newline at end of file
diff --git a/Maui.DataGrid/DataGrid.xaml b/Maui.DataGrid/DataGrid.xaml
index 0cf68ee..3ea87d6 100644
--- a/Maui.DataGrid/DataGrid.xaml
+++ b/Maui.DataGrid/DataGrid.xaml
@@ -9,7 +9,6 @@
       CompressedLayout.IsHeadless="True">
     <ContentView.Resources>
         <ResourceDictionary>
-            <local:BoolToSelectionModeConverter x:Key="boolToSelectionMode" />
             <!--Default Header Style-->
             <Style x:Key="DefaultHeaderStyle" TargetType="Label">
                 <Setter Property="FontAttributes" Value="Bold" />
@@ -43,14 +42,15 @@
         <RefreshView Grid.Row="1" x:Name="_refreshView" Grid.RowSpan="2" Command="{Binding PullToRefreshCommand, Source={Reference self}}"
                      IsRefreshing="{Binding IsRefreshing, Source={Reference self}, Mode=TwoWay}" IsEnabled="{Binding RefreshingEnabled, Source={Reference self}}">
                 <!--  Set all platforms to use MeasureFirstItem when this bug is resolved https://github.com/dotnet/maui/issues/7562  -->
-                <CollectionView
+            <CollectionView
                     x:Name="_collectionView"
                     WidthRequest="{Binding WidthRequest, Source={Reference self}}"
                     BackgroundColor="{Binding BorderColor, Source={Reference self}}"
                     SelectedItem="{Binding SelectedItem, Source={Reference self}, Mode=TwoWay}"
+                    SelectedItems="{Binding SelectedItems, Source={Reference self}, Mode=TwoWay}"
                     ItemSizingStrategy="{Binding ItemSizingStrategy, Source={Reference self}}"
-                    SelectionMode="{Binding SelectionEnabled, Source={Reference self}, Converter={StaticResource boolToSelectionMode}}">
-                    <CollectionView.ItemTemplate>
+                    SelectionMode="{Binding SelectionMode, Source={Reference self}}">
+                <CollectionView.ItemTemplate>
                         <DataTemplate>
                             <local:DataGridRow DataGrid="{Reference self}" RowToEdit="{Binding RowToEdit, Source={Reference self}}" HeightRequest="{Binding RowHeight, Source={Reference self}, Mode=OneTime}" />
                         </DataTemplate>
diff --git a/Maui.DataGrid/DataGrid.xaml.cs b/Maui.DataGrid/DataGrid.xaml.cs
index bc2550f..2be094e 100644
--- a/Maui.DataGrid/DataGrid.xaml.cs
+++ b/Maui.DataGrid/DataGrid.xaml.cs
@@ -270,7 +270,7 @@ private void SortAndPaginate(SortData? sortData = null)
         BindablePropertyExtensions.Create<DataGrid, Color>(Color.FromRgb(128, 144, 160),
             coerceValue: (b, v) =>
             {
-                if (!((DataGrid)b).SelectionEnabled)
+                if (((DataGrid)b).SelectionMode == SelectionMode.None)
                 {
                     throw new InvalidOperationException("DataGrid must have SelectionEnabled to set ActiveRowColor");
                 }
@@ -540,7 +540,7 @@ private void SortAndPaginate(SortData? sortData = null)
             },
             coerceValue: (b, v) =>
             {
-                if (v is null || b is not DataGrid self || !self.SelectionEnabled)
+                if (v is null || b is not DataGrid self || self.SelectionMode == SelectionMode.None)
                 {
                     return null;
                 }
@@ -554,6 +554,38 @@ private void SortAndPaginate(SortData? sortData = null)
             }
         );
 
+    /// <summary>
+    /// Gets or sets the selected items in the DataGrid.
+    /// </summary>
+    public static readonly BindableProperty SelectedItemsProperty =
+        BindablePropertyExtensions.Create<DataGrid, ObservableRangeCollection<object>>([], BindingMode.TwoWay,
+            propertyChanged: (b, _, n) =>
+            {
+                var self = (DataGrid)b;
+                if (self._collectionView.SelectedItems != n)
+                {
+                    self._collectionView.SelectedItems = n;
+                }
+            },
+            coerceValue: (b, v) =>
+            {
+                if (v is null || b is not DataGrid self || self.SelectionMode == SelectionMode.None)
+                {
+                    return null;
+                }
+
+                foreach (var selectedItem in v)
+                {
+                    if (!self.InternalItems.Contains(selectedItem))
+                    {
+                        return null;
+                    }
+                }
+
+                return null;
+            }
+        );
+
     /// <summary>
     /// Gets or sets a value indicating whether selection is enabled in the DataGrid.
     /// </summary>
@@ -568,6 +600,32 @@ private void SortAndPaginate(SortData? sortData = null)
                 }
             });
 
+    /// <summary>
+    /// Gets or sets a value indicating whether selection is enabled in the DataGrid.
+    /// </summary>
+    public static readonly BindableProperty SelectionModeProperty =
+        BindablePropertyExtensions.Create<DataGrid, SelectionMode>(SelectionMode.Single, BindingMode.TwoWay,
+            propertyChanged: (b, _, n) =>
+            {
+                var self = (DataGrid)b;
+
+                switch (n)
+                {
+                    case SelectionMode.None:
+                        self.SelectedItem = null;
+                        self.SelectedItems.Clear();
+                        break;
+                    case SelectionMode.Single:
+                        self.SelectedItems.Clear();
+                        break;
+                    case SelectionMode.Multiple:
+                        self.SelectedItem = null;
+                        break;
+                }
+
+                self._collectionView.SelectionMode = n;
+            });
+
     /// <summary>
     /// Gets or sets a value indicating whether refreshing is enabled in the DataGrid.
     /// </summary>
@@ -938,12 +996,12 @@ public bool PaginationEnabled
     }
 
     /// <summary>
-    /// Enables selection in dataGrid. Default value is True
+    /// Set the SelectionMode for the DataGrid. Default value is Single
     /// </summary>
-    public bool SelectionEnabled
+    public SelectionMode SelectionMode
     {
-        get => (bool)GetValue(SelectionEnabledProperty);
-        set => SetValue(SelectionEnabledProperty, value);
+        get => (SelectionMode)GetValue(SelectionModeProperty);
+        set => SetValue(SelectionModeProperty, value);
     }
 
     /// <summary>
@@ -955,6 +1013,15 @@ public object? SelectedItem
         set => SetValue(SelectedItemProperty, value);
     }
 
+    /// <summary>
+    /// Selected items
+    /// </summary>
+    public ObservableCollection<object> SelectedItems
+    {
+        get => (ObservableCollection<object>)GetValue(SelectedItemsProperty);
+        set => SetValue(SelectedItemsProperty, value);
+    }
+
     /// <summary>
     /// Executes the command when refreshing via pull
     /// </summary>
@@ -1081,7 +1148,7 @@ protected override void OnParentSet()
         {
             _collectionView.SelectionChanged -= OnSelectionChanged;
         }
-        else if (SelectionEnabled)
+        else
         {
             _collectionView.SelectionChanged -= OnSelectionChanged;
             _collectionView.SelectionChanged += OnSelectionChanged;
@@ -1145,7 +1212,49 @@ private void OnColumnsChanged(object? sender, NotifyCollectionChangedEventArgs e
 
     private void OnSelectionChanged(object? sender, SelectionChangedEventArgs e)
     {
-        SelectedItem = _collectionView.SelectedItem;
+        switch (SelectionMode)
+        {
+            case SelectionMode.Single:
+                var collectionView = sender as CollectionView;
+
+                if (e.CurrentSelection.Count > 1)
+                {
+                    collectionView?.SelectedItems.Clear();
+                }
+
+                SelectedItem = collectionView?.SelectedItem;
+
+                break;
+
+            case SelectionMode.Multiple:
+                var isChanged = false;
+
+                if (e.CurrentSelection.Count == SelectedItems.Count)
+                {
+                    for (var i = 0; i < e.CurrentSelection.Count; i++)
+                    {
+                        if (SelectedItems[i] != e.CurrentSelection[i])
+                        {
+                            isChanged = true;
+                        }
+                    }
+                }
+
+                if (isChanged && SelectedItems is ObservableRangeCollection<object> selectedItems)
+                {
+                    selectedItems.ReplaceRange(e.CurrentSelection);
+                }
+
+                break;
+
+            case SelectionMode.None:
+                if (e.CurrentSelection.Count != 0)
+                {
+                    throw new InvalidOperationException("Item(s) selected when SelectionMode is None");
+                }
+
+                break;
+        }
 
         _itemSelectedEventManager.HandleEvent(this, e, nameof(ItemSelected));
     }
@@ -1154,9 +1263,28 @@ private void OnItemsSourceCollectionChanged(object? sender, NotifyCollectionChan
     {
         SortAndPaginate();
 
-        if (SelectedItem != null && InternalItems?.Contains(SelectedItem) != true)
+        switch (SelectionMode)
         {
-            SelectedItem = null;
+            case SelectionMode.Single:
+                if (SelectedItem != null && InternalItems?.Contains(SelectedItem) != true)
+                {
+                    SelectedItem = null;
+                }
+
+                break;
+            case SelectionMode.Multiple:
+                if (SelectedItems != null)
+                {
+                    foreach (var selectedItem in SelectedItems)
+                    {
+                        if (!InternalItems.Contains(selectedItem))
+                        {
+                            SelectedItems.Clear();
+                        }
+                    }
+                }
+
+                break;
         }
     }
 
diff --git a/Maui.DataGrid/DataGridRow.cs b/Maui.DataGrid/DataGridRow.cs
index 5bd2276..68a0c86 100644
--- a/Maui.DataGrid/DataGridRow.cs
+++ b/Maui.DataGrid/DataGridRow.cs
@@ -50,7 +50,7 @@ public object RowToEdit
                     }
                 }
 
-                if (n is DataGrid newDataGrid && newDataGrid.SelectionEnabled)
+                if (n is DataGrid newDataGrid)
                 {
                     newDataGrid.ItemSelected += self.DataGrid_ItemSelected;
                     newDataGrid.Columns.CollectionChanged += self.OnColumnsChanged;
@@ -338,7 +338,7 @@ private Grid WrapViewInGrid(View view)
 
     private void UpdateColors()
     {
-        _hasSelected = DataGrid.SelectedItem == BindingContext;
+        _hasSelected = DataGrid.SelectedItem == BindingContext || DataGrid.SelectedItems.Contains(BindingContext);
         var rowIndex = DataGrid.InternalItems?.IndexOf(BindingContext) ?? -1;
 
         if (rowIndex < 0)
@@ -346,7 +346,7 @@ private void UpdateColors()
             return;
         }
 
-        _bgColor = DataGrid.SelectionEnabled && _hasSelected
+        _bgColor = DataGrid.SelectionMode != SelectionMode.None && _hasSelected
                 ? DataGrid.ActiveRowColor
                 : DataGrid.RowsBackgroundColorPalette.GetColor(rowIndex, BindingContext);
         _textColor = DataGrid.RowsTextColorPalette.GetColor(rowIndex, BindingContext);
@@ -401,7 +401,7 @@ private void OnVisibilityChanged(object? sender, EventArgs e)
 
     private void DataGrid_ItemSelected(object? sender, SelectionChangedEventArgs e)
     {
-        if (_hasSelected || (e.CurrentSelection.Count > 0 && e.CurrentSelection[^1] == BindingContext))
+        if (_hasSelected || (e.CurrentSelection.Count > 0 && e.CurrentSelection.Any(s => s == BindingContext)))
         {
             UpdateColors();
         }