Add batch DLL swap: select multiple games and apply in one pass

src/Data/BatchSwapResult.cs

@@ -0,0 +1,39 @@
+using DLSS_Swapper.Helpers;
+
+namespace DLSS_Swapper.Data;
+
+public enum BatchSwapStatus
+{
+    // Covers successfully applied changes: DLL swaps, DLL restores, and preset updates.
+    Swapped,
+    Skipped,
+    Error,
+}
+
+public class BatchSwapResult
+{
+    public string GameTitle { get; init; } = string.Empty;
+    public BatchSwapStatus Status { get; init; }
+
+    // Localised, game-agnostic action label built on the UI thread before the
+    // worker starts (e.g. "DLSS → 3.7.0" or "Preset DLSS → D"). Never resolved
+    // inside the batch worker.
+    public string ActionLabel { get; init; } = string.Empty;
+
+    // Resource key explaining a skip. Resolved lazily so it is read on the UI
+    // thread at display time, not inside the batch worker.
+    public string ReasonKey { get; init; } = string.Empty;
+
+    // Raw (unlocalised) message from the game operation when Status is Error.
+    public string ErrorMessage { get; init; } = string.Empty;
+
+    public bool PromptToRelaunchAsAdmin { get; init; }
+
+    public string DisplayText => Status switch
+    {
+        BatchSwapStatus.Skipped => $"{GameTitle} — {ActionLabel} — {ResourceHelper.GetString(ReasonKey)}",
+        BatchSwapStatus.Error when string.IsNullOrEmpty(ErrorMessage) => $"{GameTitle} — {ActionLabel} — {ResourceHelper.GetString("GamesPage_Batch_Error_Generic")}",
+        BatchSwapStatus.Error => $"{GameTitle} — {ActionLabel} — {ResourceHelper.GetFormattedResourceTemplate("GamesPage_Batch_Error_PossiblyPartialTemplate", ErrorMessage)}",
+        _ => $"{GameTitle} — {ActionLabel}",
+    };
+}

src/Data/DLLManager.cs

@@ -787,6 +787,40 @@ public string GetAssetTypeName(GameAssetType assetType)
         };
     }
 
+    /// <summary>
+    /// Decides if a batch swap can apply dllRecord to game. ReasonKey is a resource
+    /// key describing why not. Mirrors the DLSS 1.x vs 2/3 rule from
+    /// DLLPickerControlModel, but evaluates every DLSS asset instead of only the
+    /// first: UpdateDllAsync overwrites every matching asset with the same dll, so
+    /// games mixing generations must be skipped.
+    /// </summary>
+    internal static (bool Compatible, string ReasonKey) GetBatchCompatibility(Game game, DLLRecord dllRecord)
+    {
+        var existingAssets = game.GameAssets.Where(x => x.AssetType == dllRecord.AssetType).ToList();
+        if (existingAssets.Count == 0)
+        {
+            return (false, "GamesPage_Batch_Skipped_NoAsset");
+        }
+
+        if (dllRecord.AssetType == GameAssetType.DLSS)
+        {
+            var hasV1Assets = existingAssets.Any(x => x.Version.StartsWith("1."));
+            var hasV2PlusAssets = existingAssets.Any(x => x.Version.StartsWith("1.") == false);
+
+            if (hasV1Assets == true && hasV2PlusAssets == true)
+            {
+                return (false, "GamesPage_Batch_Skipped_MixedGenerations");
+            }
+
+            var recordIsV1 = dllRecord.Version.StartsWith("1.");
+            if (hasV1Assets != recordIsV1)
+            {
+                return (false, "GamesPage_Batch_Skipped_Incompatible");
+            }
+        }
+
+        return (true, string.Empty);
+    }
 
     public GameAssetType GetAssetBackupType(GameAssetType assetType)
     {

src/Data/DLLRecord.cs

@@ -283,6 +283,11 @@ internal void CancelDownload()
         try
         {
             LocalRecord.FileDownloader = fileDownloader;
+            // Reset stale error state from a previous failed attempt, otherwise a
+            // cancelled retry is misreported as an error by observers that
+            // distinguish cancel from error via HasDownloadError.
+            LocalRecord.HasDownloadError = false;
+            LocalRecord.DownloadErrorMessage = string.Empty;
             NotifyPropertyChanged(nameof(LocalRecord));
 
 

src/Pages/GameGridPage.xaml

@@ -97,6 +97,20 @@
 
             <GridView PointerWheelChanged="MainGridView_PointerWheelChanged" ManipulationMode="None" x:Name="MainGridView" ItemsSource="{x:Bind CurrentCollectionView, Mode=OneWay}" SelectionMode="None" IsItemClickEnabled="True" ItemClick="GridAndListView_ItemClick" Padding="20"  >
 
+                <GridView.Resources>
+                    <!-- White selection checkmark backdrop for contrast against varied cover art (default uses the accent color). -->
+                    <SolidColorBrush x:Key="GridViewItemCheckBoxSelectedBrush" Color="White" />
+                    <SolidColorBrush x:Key="GridViewItemCheckBoxSelectedPointerOverBrush" Color="White" />
+                    <SolidColorBrush x:Key="GridViewItemCheckBoxSelectedPressedBrush" Color="#DDDDDD" />
+                    <SolidColorBrush x:Key="GridViewItemCheckBrush" Color="Black" />
+
+                    <!-- The item container draws behind the cover art, so its selected background only
+                         shows through the padding added below, reading as an accent frame. -->
+                    <StaticResource x:Key="GridViewItemBackgroundSelected" ResourceKey="AccentFillColorDefaultBrush" />
+                    <StaticResource x:Key="GridViewItemBackgroundSelectedPointerOver" ResourceKey="AccentFillColorSecondaryBrush" />
+                    <StaticResource x:Key="GridViewItemBackgroundSelectedPressed" ResourceKey="AccentFillColorTertiaryBrush" />
+                </GridView.Resources>
+
                 <GridView.GroupStyle>
                     <GroupStyle HidesIfEmpty="True">
                         <GroupStyle.HeaderTemplate>
@@ -115,6 +129,10 @@
                         <Setter Property="VerticalContentAlignment" Value="Stretch"/>
                         <Setter Property="Margin" Value="8"/>
                         <Setter Property="BorderThickness" Value="0"/>
+                        <!-- Padding + matching corner radius are what make the selected background
+                             visible as a frame around the 8px-rounded card content. -->
+                        <Setter Property="Padding" Value="3"/>
+                        <Setter Property="CornerRadius" Value="11"/>
                     </Style>
                 </GridView.ItemContainerStyle>
 
@@ -231,22 +249,27 @@
                         <FontIcon Glyph="&#xE946;" />
                     </AppBarButton.Content>
                 </AppBarButton>
-                <AppBarButton Label="{x:Bind ViewModel.TranslationProperties.AddGameText, Mode=OneWay}" Command="{x:Bind ViewModel.AddManualGameButtonCommand}" IsEnabled="{x:Bind ViewModel.IsGameListLoading, Converter={StaticResource BoolNegationConverter}, Mode=OneWay}">
+                <AppBarButton Label="{x:Bind ViewModel.TranslationProperties.AddGameText, Mode=OneWay}" Command="{x:Bind ViewModel.AddManualGameButtonCommand}" IsEnabled="{x:Bind ViewModel.CanAddGameAndChangeView, Mode=OneWay}">
                     <AppBarButton.Content>
                         <FontIcon Glyph="&#xE710;" />
                     </AppBarButton.Content>
                 </AppBarButton>
-                <AppBarButton Label="{x:Bind ViewModel.TranslationProperties.RefreshText, Mode=OneWay}" Command="{x:Bind ViewModel.RefreshGamesButtonCommand}" IsEnabled="{x:Bind ViewModel.IsLoading, Converter={StaticResource BoolNegationConverter}, Mode=OneWay}">
+                <AppBarButton Label="{x:Bind ViewModel.TranslationProperties.RefreshText, Mode=OneWay}" Command="{x:Bind ViewModel.RefreshGamesButtonCommand}" IsEnabled="{x:Bind ViewModel.CanRefresh, Mode=OneWay}">
                     <AppBarButton.Content>
                         <FontIcon Glyph="&#xE72C;" />
                     </AppBarButton.Content>
                 </AppBarButton>
-                <AppBarButton Icon="Filter" Label="{x:Bind ViewModel.TranslationProperties.FilterText, Mode=OneWay}" Command="{x:Bind ViewModel.FilterGamesButtonCommand}" IsEnabled="{x:Bind ViewModel.IsGameListLoading, Converter={StaticResource BoolNegationConverter}, Mode=OneWay}">
+                <AppBarButton Label="{x:Bind ViewModel.TranslationProperties.BulkSwapText, Mode=OneWay}" Command="{x:Bind ViewModel.ToggleSelectionModeCommand}" IsEnabled="{x:Bind ViewModel.IsGameListLoading, Converter={StaticResource BoolNegationConverter}, Mode=OneWay}">
+                    <AppBarButton.Content>
+                        <FontIcon Glyph="&#xE762;" />
+                    </AppBarButton.Content>
+                </AppBarButton>
+                <AppBarButton Icon="Filter" Label="{x:Bind ViewModel.TranslationProperties.FilterText, Mode=OneWay}" Command="{x:Bind ViewModel.FilterGamesButtonCommand}" IsEnabled="{x:Bind ViewModel.CanUseFilter, Mode=OneWay}">
                     <AppBarButton.Content>
                         <FontIcon Glyph="&#xE71C;" />
                     </AppBarButton.Content>
                 </AppBarButton>
-                <AppBarButton Label="{x:Bind ViewModel.TranslationProperties.ViewTypeText, Mode=OneWay}" Content="{x:Bind ViewModel.GameGridViewIcon, Mode=OneWay}">
+                <AppBarButton Label="{x:Bind ViewModel.TranslationProperties.ViewTypeText, Mode=OneWay}" Content="{x:Bind ViewModel.GameGridViewIcon, Mode=OneWay}" IsEnabled="{x:Bind ViewModel.CanAddGameAndChangeView, Mode=OneWay}">
                     <AppBarButton.Flyout>
                         <MenuFlyout>
                             <MenuFlyoutItem Text="{x:Bind ViewModel.TranslationProperties.GridViewText, Mode=OneWay}" Command="{x:Bind ViewModel.ChangeGameGridViewCommand}" CommandParameter="{x:Bind pages:GameGridViewType.GridView}" />
@@ -267,6 +290,25 @@
         </Grid>
 
         <ContentControl x:Name="MainContentControl" Grid.Row="1" HorizontalAlignment="Stretch" HorizontalContentAlignment="Stretch" VerticalAlignment="Stretch" Content="{x:Bind ViewModel, Mode=OneWay}" ContentTemplateSelector="{StaticResource TemplateSelector}" />
-
+
+        <Border Grid.Row="1"
+                VerticalAlignment="Bottom"
+                HorizontalAlignment="Center"
+                Margin="0,0,0,24"
+                Padding="16,8"
+                CornerRadius="8"
+                BorderThickness="1"
+                Background="{ThemeResource CardBackgroundFillColorDefaultBrush}"
+                BorderBrush="{ThemeResource CardStrokeColorDefaultBrush}"
+                Visibility="{x:Bind ViewModel.IsSelectionMode, Mode=OneWay, Converter={StaticResource BoolToVisibilityConverter}}">
+            <StackPanel Orientation="Horizontal" Spacing="12">
+                <TextBlock Text="{x:Bind ViewModel.SelectedGamesCountText, Mode=OneWay}" VerticalAlignment="Center" />
+                <Button Content="{x:Bind ViewModel.TranslationProperties.SelectAllText, Mode=OneWay}" Command="{x:Bind ViewModel.SelectAllVisibleCommand}" />
+                <Button Content="{x:Bind ViewModel.TranslationProperties.SelectNoneText, Mode=OneWay}" Command="{x:Bind ViewModel.ClearSelectionCommand}" />
+                <Button Style="{StaticResource AccentButtonStyle}" Content="{x:Bind ViewModel.TranslationProperties.SelectDllsText, Mode=OneWay}" Command="{x:Bind ViewModel.ApplyBatchDllCommand}" />
+                <Button Content="{x:Bind ViewModel.TranslationProperties.CloseText, Mode=OneWay}" Command="{x:Bind ViewModel.ToggleSelectionModeCommand}" />
+            </StackPanel>
+        </Border>
+
     </Grid>
 </Page>

src/Pages/GameGridPage.xaml.cs

@@ -2,8 +2,11 @@
 using DLSS_Swapper.UserControls;
 using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
+using Microsoft.UI.Xaml.Data;
 using Microsoft.UI.Xaml.Input;
 using System;
+using System.Collections.Generic;
+using System.Linq;
 using System.Threading.Tasks;
 using Windows.System;
 using AsyncAwaitBestPractices;
@@ -192,4 +195,134 @@ private void ClearSearchBox_Click(object sender, RoutedEventArgs e)
     {
         SearchBox.Text = string.Empty;
     }
+
+    internal string SearchText => SearchBox.Text;
+
+    bool _isSyncingSelection;
+    int _viewSyncGeneration;
+
+    ListViewBase? GetActiveListControl()
+    {
+        return MainContentControl.ContentTemplateRoot as ListViewBase;
+    }
+
+    internal void EnterSelectionMode()
+    {
+        var listControl = GetActiveListControl();
+        if (listControl is null)
+        {
+            return;
+        }
+
+        listControl.SelectionMode = ListViewSelectionMode.Multiple;
+        listControl.IsItemClickEnabled = false;
+        listControl.SelectionChanged += ListControl_SelectionChanged;
+        ResyncVisualSelection();
+    }
+
+    internal void ExitSelectionMode()
+    {
+        var listControl = GetActiveListControl();
+        if (listControl is null)
+        {
+            return;
+        }
+
+        listControl.SelectionChanged -= ListControl_SelectionChanged;
+        _isSyncingSelection = true;
+        try
+        {
+            if (listControl.Items.Count > 0)
+            {
+                listControl.DeselectRange(new ItemIndexRange(0, (uint)listControl.Items.Count));
+            }
+        }
+        finally
+        {
+            _isSyncingSelection = false;
+        }
+        listControl.SelectionMode = ListViewSelectionMode.None;
+        listControl.IsItemClickEnabled = true;
+    }
+
+    internal IEnumerable<Game> GetDistinctVisibleGames()
+    {
+        var list = GetActiveListControl();
+        return list is null ? Enumerable.Empty<Game>() : list.Items.OfType<Game>().Distinct().ToList();
+    }
+
+    void ListControl_SelectionChanged(object sender, SelectionChangedEventArgs e)
+    {
+        if (_isSyncingSelection == true)
+        {
+            return;
+        }
+
+        ViewModel.UpdateSelection(e.AddedItems, e.RemovedItems);
+        ResyncVisualSelection();
+    }
+
+    internal void BeginSuppressSelectionEvents()
+    {
+        _isSyncingSelection = true;
+        _viewSyncGeneration++;
+    }
+
+    // Called after CurrentCollectionView changes while selection mode is active.
+    // Swapping the ItemsSource clears the list's visual selection, so it is
+    // re-applied from the view model's SelectedGames afterwards.
+    internal void ResyncVisualSelectionAfterViewChange()
+    {
+        var generation = _viewSyncGeneration;
+        var enqueued = DispatcherQueue.TryEnqueue(() =>
+        {
+            if (generation != _viewSyncGeneration)
+            {
+                // A newer view change has already been requested; ignore this stale callback.
+                return;
+            }
+
+            ResyncVisualSelection();
+            ViewModel.NotifySelectionChanged();
+        });
+
+        // BeginSuppressSelectionEvents set _isSyncingSelection before the ItemsSource
+        // swap; if the resync could not be queued, nothing else would ever reset it
+        // and all selection events would be ignored from here on.
+        if (enqueued == false)
+        {
+            _isSyncingSelection = false;
+        }
+    }
+
+    internal void ResyncVisualSelection()
+    {
+        var listControl = GetActiveListControl();
+        if (listControl is null)
+        {
+            _isSyncingSelection = false;
+            return;
+        }
+
+        _isSyncingSelection = true;
+        try
+        {
+            if (listControl.Items.Count > 0)
+            {
+                listControl.DeselectRange(new ItemIndexRange(0, (uint)listControl.Items.Count));
+            }
+
+            for (var index = 0; index < listControl.Items.Count; index++)
+            {
+                if (listControl.Items[index] is Game game && ViewModel.SelectedGames.Contains(game))
+                {
+                    listControl.SelectRange(new ItemIndexRange(index, 1));
+                }
+            }
+        }
+        finally
+        {
+            _isSyncingSelection = false;
+        }
+    }
 }