From a06aafc0a69a317942db475f6b5a431fcc72e7b1 Mon Sep 17 00:00:00 2001
From: hishitetsu <66369541+hishitetsu@users.noreply.github.com>
Date: Wed, 7 Feb 2024 00:27:09 +0900
Subject: [PATCH] Fix: Fixed crash that could occur when dragging in grouped
 grid layout (#14654)

---
 src/Files.App/Views/Layouts/BaseLayoutPage.cs |  6 +--
 .../Views/Layouts/GridLayoutPage.xaml         |  2 +
 .../Views/Layouts/GridLayoutPage.xaml.cs      | 41 +++++++++++++++++++
 3 files changed, 46 insertions(+), 3 deletions(-)

diff --git a/src/Files.App/Views/Layouts/BaseLayoutPage.cs b/src/Files.App/Views/Layouts/BaseLayoutPage.cs
index 83fcb600934d..a11f1d72cb42 100644
--- a/src/Files.App/Views/Layouts/BaseLayoutPage.cs
+++ b/src/Files.App/Views/Layouts/BaseLayoutPage.cs
@@ -958,7 +958,7 @@ protected virtual void Page_CharacterReceived(UIElement sender, CharacterReceive
 			}
 		}
 
-		protected void FileList_DragItemsStarting(object sender, DragItemsStartingEventArgs e)
+		protected virtual void FileList_DragItemsStarting(object sender, DragItemsStartingEventArgs e)
 		{
 			try
 			{
@@ -1094,7 +1094,7 @@ private async void Item_DragOver(object sender, DragEventArgs e)
 			}
 		}
 
-		private async void Item_Drop(object sender, DragEventArgs e)
+		protected virtual async void Item_Drop(object sender, DragEventArgs e)
 		{
 			var deferral = e.GetDeferral();
 
@@ -1282,7 +1282,7 @@ protected void ItemsLayout_DragOver(object sender, DragEventArgs e)
 			CommandsViewModel?.DragOverCommand?.Execute(e);
 		}
 
-		protected void ItemsLayout_Drop(object sender, DragEventArgs e)
+		protected virtual void ItemsLayout_Drop(object sender, DragEventArgs e)
 		{
 			CommandsViewModel?.DropCommand?.Execute(e);
 		}
diff --git a/src/Files.App/Views/Layouts/GridLayoutPage.xaml b/src/Files.App/Views/Layouts/GridLayoutPage.xaml
index f5adce4f7863..1c10777f4d50 100644
--- a/src/Files.App/Views/Layouts/GridLayoutPage.xaml
+++ b/src/Files.App/Views/Layouts/GridLayoutPage.xaml
@@ -819,7 +819,9 @@
 					CanDragItems="{x:Bind AllowItemDrag, Mode=OneWay}"
 					ContainerContentChanging="FileList_ContainerContentChanging"
 					DoubleTapped="FileList_DoubleTapped"
+					DragEnter="ItemsLayout_DragEnter"
 					DragItemsStarting="FileList_DragItemsStarting"
+					DragLeave="ItemsLayout_DragLeave"
 					DragOver="ItemsLayout_DragOver"
 					Drop="ItemsLayout_Drop"
 					FocusVisualPrimaryThickness="0"
diff --git a/src/Files.App/Views/Layouts/GridLayoutPage.xaml.cs b/src/Files.App/Views/Layouts/GridLayoutPage.xaml.cs
index 3104c6e4ed73..e9d351fb4271 100644
--- a/src/Files.App/Views/Layouts/GridLayoutPage.xaml.cs
+++ b/src/Files.App/Views/Layouts/GridLayoutPage.xaml.cs
@@ -639,6 +639,47 @@ private void SelectionCheckbox_PointerCanceled(object sender, PointerRoutedEvent
 			UpdateCheckboxVisibility((sender as FrameworkElement)!.FindAscendant<GridViewItem>()!, false);
 		}
 
+		// To avoid crashes, disable scrolling when drag-and-drop if grouped. (#14484)
+		protected override void FileList_DragItemsStarting(object sender, DragItemsStartingEventArgs e)
+		{
+			if (ParentShellPageInstance?.FilesystemViewModel.FilesAndFolders.IsGrouped ?? false)
+				ScrollViewer.SetVerticalScrollMode(FileList, ScrollMode.Disabled);
+
+			base.FileList_DragItemsStarting(sender, e);
+
+			if (ParentShellPageInstance?.FilesystemViewModel.FilesAndFolders.IsGrouped ?? false &&
+				e.Cancel)
+				ScrollViewer.SetVerticalScrollMode(FileList, ScrollMode.Auto);
+		}
+
+		private void ItemsLayout_DragEnter(object sender, DragEventArgs e)
+		{
+			if (ParentShellPageInstance?.FilesystemViewModel.FilesAndFolders.IsGrouped ?? false)
+				ScrollViewer.SetVerticalScrollMode(FileList, ScrollMode.Disabled);
+		}
+
+		private void ItemsLayout_DragLeave(object sender, DragEventArgs e)
+		{
+			if (ParentShellPageInstance?.FilesystemViewModel.FilesAndFolders.IsGrouped ?? false)
+				ScrollViewer.SetVerticalScrollMode(FileList, ScrollMode.Auto);
+		}
+
+		protected override void ItemsLayout_Drop(object sender, DragEventArgs e)
+		{
+			if (ParentShellPageInstance?.FilesystemViewModel.FilesAndFolders.IsGrouped ?? false)
+				ScrollViewer.SetVerticalScrollMode(FileList, ScrollMode.Auto);
+
+			base.ItemsLayout_Drop(sender, e);
+		}
+
+		protected override void Item_Drop(object sender, DragEventArgs e)
+		{
+			if (ParentShellPageInstance?.FilesystemViewModel.FilesAndFolders.IsGrouped ?? false)
+				ScrollViewer.SetVerticalScrollMode(FileList, ScrollMode.Auto);
+
+			base.Item_Drop(sender, e);
+		}
+
 		private void UpdateCheckboxVisibility(object sender, bool isPointerOver)
 		{
 			if (sender is GridViewItem control && control.FindDescendant<UserControl>() is UserControl userControl)