Feature: Added support for creating alternate data streams

src/Files.App/Actions/FileSystem/CreateAlternateDataStreamAction.cs

@@ -0,0 +1,115 @@
+// Copyright (c) 2024 Files Community
+// Licensed under the MIT License. See the LICENSE.
+
+using Microsoft.UI.Xaml.Controls;
+using System.IO;
+using Windows.Foundation.Metadata;
+
+namespace Files.App.Actions
+{
+	internal sealed class CreateAlternateDataStreamAction : BaseUIAction, IAction
+	{
+		private readonly IContentPageContext context;
+
+		private static readonly IFoldersSettingsService FoldersSettingsService = Ioc.Default.GetRequiredService<IFoldersSettingsService>();
+
+		public string Label
+			=> "CreateAlternateDataStream".GetLocalizedResource();
+
+		public string Description
+			=> "CreateAlternateDataStreamDescription".GetLocalizedResource();
+
+		public override bool IsExecutable =>
+			context.HasSelection &&
+			context.CanCreateItem &&
+			(context.ShellPage?.ShellViewModel.WorkingDirectory != Path.GetPathRoot(context.ShellPage?.ShellViewModel.WorkingDirectory)) &&
+			UIHelpers.CanShowDialog;
+
+		public CreateAlternateDataStreamAction()
+		{
+			context = Ioc.Default.GetRequiredService<IContentPageContext>();
+
+			context.PropertyChanged += Context_PropertyChanged;
+		}
+
+		public async Task ExecuteAsync(object? parameter = null)
+		{
+			var nameDialog = DynamicDialogFactory.GetFor_CreateAlternateDataStreamDialog();
+			await nameDialog.TryShowAsync();
+
+			if (nameDialog.DynamicResult != DynamicDialogResult.Primary)
+				return;
+
+			var userInput = nameDialog.ViewModel.AdditionalData as string;
+			await Task.WhenAll(context.SelectedItems.Select(async selectedItem =>
+			{
+				var isDateOk = Win32Helper.GetFileDateModified(selectedItem.ItemPath, out var dateModified);
+				var isReadOnly = Win32Helper.HasFileAttribute(selectedItem.ItemPath, System.IO.FileAttributes.ReadOnly);
+
+				// Unset read-only attribute (#7534)
+				if (isReadOnly)
+					Win32Helper.UnsetFileAttribute(selectedItem.ItemPath, System.IO.FileAttributes.ReadOnly);
+
+				if (!Win32Helper.WriteStringToFile($"{selectedItem.ItemPath}:{userInput}", ""))
+				{
+					var dialog = new ContentDialog
+					{
+						Title = Strings.ErrorCreatingDataStreamTitle.GetLocalizedResource(),
+						Content = Strings.ErrorCreatingDataStreamDescription.GetLocalizedResource(),
+						PrimaryButtonText = "Ok".GetLocalizedResource()
+					};
+
+					if (ApiInformation.IsApiContractPresent("Windows.Foundation.UniversalApiContract", 8))
+						dialog.XamlRoot = MainWindow.Instance.Content.XamlRoot;
+
+					await dialog.TryShowAsync();
+				}
+
+				// Restore read-only attribute (#7534)
+				if (isReadOnly)
+					Win32Helper.SetFileAttribute(selectedItem.ItemPath, System.IO.FileAttributes.ReadOnly);
+
+				// Restore date modified
+				if (isDateOk)
+					Win32Helper.SetFileDateModified(selectedItem.ItemPath, dateModified);
+			}));
+
+			if (context.ShellPage is null)
+				return;
+
+			if (FoldersSettingsService.AreAlternateStreamsVisible)
+				await context.ShellPage.Refresh_Click();
+			else
+			{
+				var dialog = new ContentDialog
+				{
+					Title = Strings.DataStreamsAreHiddenTitle.GetLocalizedResource(),
+					Content = Strings.DataStreamsAreHiddenDescription.GetLocalizedResource(),
+					PrimaryButtonText = Strings.Yes.GetLocalizedResource(),
+					SecondaryButtonText = Strings.No.GetLocalizedResource()
+				};
+
+				if (ApiInformation.IsApiContractPresent("Windows.Foundation.UniversalApiContract", 8))
+					dialog.XamlRoot = MainWindow.Instance.Content.XamlRoot;
+
+				var result = await dialog.TryShowAsync();
+				if (result == ContentDialogResult.Primary)
+				{
+					FoldersSettingsService.AreAlternateStreamsVisible = true;
+					await context.ShellPage.Refresh_Click();
+				}
+			}
+		}
+
+		private void Context_PropertyChanged(object? sender, PropertyChangedEventArgs e)
+		{
+			switch (e.PropertyName)
+			{
+				case nameof(IContentPageContext.HasSelection):
+				case nameof(IContentPageContext.CanCreateItem):
+					OnPropertyChanged(nameof(IsExecutable));
+					break;
+			}
+		}
+	}
+}

src/Files.App/Data/Commands/Manager/CommandCodes.cs

@@ -42,6 +42,7 @@ public enum CommandCodes
 		CreateFolder,
 		CreateFolderWithSelection,
 		AddItem,
+		CreateAlternateDataStream,
 		CreateShortcut,
 		CreateShortcutFromDialog,
 		EmptyRecycleBin,

src/Files.App/Data/Commands/Manager/CommandManager.cs

@@ -67,6 +67,7 @@ public IRichCommand this[HotKey hotKey]
 		public IRichCommand RestoreAllRecycleBin => commands[CommandCodes.RestoreAllRecycleBin];
 		public IRichCommand RefreshItems => commands[CommandCodes.RefreshItems];
 		public IRichCommand Rename => commands[CommandCodes.Rename];
+		public IRichCommand CreateAlternateDataStream => commands[CommandCodes.CreateAlternateDataStream];
 		public IRichCommand CreateShortcut => commands[CommandCodes.CreateShortcut];
 		public IRichCommand CreateShortcutFromDialog => commands[CommandCodes.CreateShortcutFromDialog];
 		public IRichCommand CreateFolder => commands[CommandCodes.CreateFolder];
@@ -263,6 +264,7 @@ public IEnumerator<IRichCommand> GetEnumerator() =>
 			[CommandCodes.RestoreAllRecycleBin] = new RestoreAllRecycleBinAction(),
 			[CommandCodes.RefreshItems] = new RefreshItemsAction(),
 			[CommandCodes.Rename] = new RenameAction(),
+			[CommandCodes.CreateAlternateDataStream] = new CreateAlternateDataStreamAction(),
 			[CommandCodes.CreateShortcut] = new CreateShortcutAction(),
 			[CommandCodes.CreateShortcutFromDialog] = new CreateShortcutFromDialogAction(),
 			[CommandCodes.CreateFolder] = new CreateFolderAction(),

src/Files.App/Data/Commands/Manager/ICommandManager.cs

@@ -51,6 +51,7 @@ public interface ICommandManager : IEnumerable<IRichCommand>
 		IRichCommand CreateFolder { get; }
 		IRichCommand CreateFolderWithSelection { get; }
 		IRichCommand AddItem { get; }
+		IRichCommand CreateAlternateDataStream { get; }
 		IRichCommand CreateShortcut { get; }
 		IRichCommand CreateShortcutFromDialog { get; }
 		IRichCommand EmptyRecycleBin { get; }

src/Files.App/Data/Contracts/IGeneralSettingsService.cs

@@ -210,6 +210,11 @@ public interface IGeneralSettingsService : IBaseSettingsService, INotifyProperty
 		/// </summary>
 		bool ShowCopyPath { get; set; }
 
+		/// <summary>
+		/// Gets or sets a value indicating whether or not to show the option to create alternate data stream.
+		/// </summary>
+		bool ShowCreateAlternateDataStream { get; set; }
+
 		/// <summary>
 		/// Gets or sets a value indicating whether or not to show the option to create a shortcut.
 		/// </summary>

src/Files.App/Data/Factories/ContentPageContextFlyoutFactory.cs

@@ -477,6 +477,11 @@ public static List<ContextMenuFlyoutItemViewModel> GetBaseItemMenuItems(
 						&& (!selectedItems.FirstOrDefault()?.IsShortcut ?? false)
 						&& !currentInstanceViewModel.IsPageTypeRecycleBin,
 				}.Build(),
+				new ContextMenuFlyoutItemViewModelBuilder(Commands.CreateAlternateDataStream)
+				{
+					IsVisible = UserSettingsService.GeneralSettingsService.ShowCreateAlternateDataStream &&
+						Commands.CreateAlternateDataStream.IsExecutable,
+				}.Build(),
 				new ContextMenuFlyoutItemViewModelBuilder(Commands.Rename)
 				{
 					IsPrimary = true,

src/Files.App/Helpers/Dialog/DialogDisplayHelper.cs

@@ -2,10 +2,7 @@
 // Licensed under the MIT License. See the LICENSE.
 
 using Files.App.Dialogs;
-using Files.App.ViewModels.Dialogs;
 using Microsoft.UI.Xaml.Controls;
-using System;
-using System.Threading.Tasks;
 
 namespace Files.App.Helpers
 {

src/Files.App/Helpers/Dialog/DynamicDialogFactory.cs

@@ -2,14 +2,11 @@
 // Licensed under the MIT License. See the LICENSE.
 
 using Files.App.Dialogs;
-using Files.App.ViewModels.Dialogs;
 using Microsoft.UI;
-using Microsoft.UI.Text;
 using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
 using Microsoft.UI.Xaml.Data;
 using Microsoft.UI.Xaml.Media;
-using Windows.ApplicationModel.DataTransfer;
 using Windows.System;
 
 namespace Files.App.Helpers
@@ -333,5 +330,79 @@ public static DynamicDialog GetFor_RenameRequiresHigherPermissions(string path)
 
 			return dialog;
 		}
+
+		public static DynamicDialog GetFor_CreateAlternateDataStreamDialog()
+		{
+			DynamicDialog? dialog = null;
+			TextBox inputText = new()
+			{
+				PlaceholderText = Strings.EnterDataStreamName.GetLocalizedResource()
+			};
+
+			TeachingTip warning = new()
+			{
+				Title = Strings.InvalidFilename_Text.GetLocalizedResource(),
+				PreferredPlacement = TeachingTipPlacementMode.Bottom,
+				DataContext = new CreateItemDialogViewModel(),
+			};
+
+			warning.SetBinding(TeachingTip.TargetProperty, new Binding()
+			{
+				Source = inputText
+			});
+			warning.SetBinding(TeachingTip.IsOpenProperty, new Binding()
+			{
+				Mode = BindingMode.OneWay,
+				Path = new PropertyPath("IsNameInvalid")
+			});
+
+			inputText.Resources.Add("InvalidNameWarningTip", warning);
+
+			inputText.TextChanged += (textBox, args) =>
+			{
+				var isInputValid = FilesystemHelpers.IsValidForFilename(inputText.Text);
+				((CreateItemDialogViewModel)warning.DataContext).IsNameInvalid = !string.IsNullOrEmpty(inputText.Text) && !isInputValid;
+				dialog!.ViewModel.DynamicButtonsEnabled = isInputValid
+														? DynamicDialogButtons.Primary | DynamicDialogButtons.Cancel
+														: DynamicDialogButtons.Cancel;
+				if (isInputValid)
+					dialog.ViewModel.AdditionalData = inputText.Text;
+			};
+
+			inputText.Loaded += (s, e) =>
+			{
+				// dispatching to the ui thread fixes an issue where the primary dialog button would steal focus
+				_ = inputText.DispatcherQueue.EnqueueOrInvokeAsync(() => inputText.Focus(FocusState.Programmatic));
+			};
+
+			dialog = new DynamicDialog(new DynamicDialogViewModel()
+			{
+				TitleText = string.Format(Strings.CreateAlternateDataStream.GetLocalizedResource()),
+				SubtitleText = null,
+				DisplayControl = new Grid()
+				{
+					MinWidth = 300d,
+					Children =
+					{
+						inputText
+					}
+				},
+				PrimaryButtonAction = (vm, e) =>
+				{
+					vm.HideDialog();
+				},
+				PrimaryButtonText = Strings.Create.GetLocalizedResource(),
+				CloseButtonText = Strings.Cancel.GetLocalizedResource(),
+				DynamicButtonsEnabled = DynamicDialogButtons.Cancel,
+				DynamicButtons = DynamicDialogButtons.Primary | DynamicDialogButtons.Cancel
+			});
+
+			dialog.Closing += (s, e) =>
+			{
+				warning.IsOpen = false;
+			};
+
+			return dialog;
+		}
 	}
 }

src/Files.App/Services/Settings/GeneralSettingsService.cs

@@ -281,6 +281,12 @@ public bool ShowCreateFolderWithSelection
 			set => Set(value);
 		}
 
+		public bool ShowCreateAlternateDataStream
+		{
+			get => Get(false);
+			set => Set(value);
+		}
+
 		public bool ShowCreateShortcut
 		{
 			get => Get(true);

src/Files.App/Strings/en-US/Resources.resw

@@ -3971,4 +3971,28 @@
   <data name="BulkRename" xml:space="preserve">
     <value>Bulk rename</value>
   </data>
+  <data name="ShowCreateAlternateDataStream" xml:space="preserve">
+    <value>Show option to create alternate data stream</value>
+  </data>
+  <data name="CreateAlternateDataStream" xml:space="preserve">
+    <value>Create alternate data stream</value>
+  </data>
+  <data name="CreateAlternateDataStreamDescription" xml:space="preserve">
+    <value>Create alternate data stream for the selected item(s)</value>
+  </data>
+  <data name="EnterDataStreamName" xml:space="preserve">
+    <value>Enter data stream name</value>
+  </data>
+  <data name="ErrorCreatingDataStreamTitle" xml:space="preserve">
+    <value>There was an error creating the alternate data stream</value>
+  </data>
+  <data name="ErrorCreatingDataStreamDescription" xml:space="preserve">
+    <value>Please note that alternate data streams only work on drives formatted as NTFS.</value>
+  </data>
+  <data name="DataStreamsAreHiddenTitle" xml:space="preserve">
+    <value>Alternate data streams are currently hidden</value>
+  </data>
+  <data name="DataStreamsAreHiddenDescription" xml:space="preserve">
+    <value>Would you like to display alternate data streams? You can modify this setting anytime from the files and folders settings page.</value>
+  </data>
 </root>

src/Files.App/ViewModels/Settings/GeneralViewModel.cs

@@ -279,6 +279,20 @@ public bool ShowCopyPath
 			}
 		}
 
+		public bool ShowCreateAlternateDataStream
+		{
+			get => UserSettingsService.GeneralSettingsService.ShowCreateAlternateDataStream;
+			set
+			{
+				if (value != UserSettingsService.GeneralSettingsService.ShowCreateAlternateDataStream)
+				{
+					UserSettingsService.GeneralSettingsService.ShowCreateAlternateDataStream = value;
+
+					OnPropertyChanged();
+				}
+			}
+		}
+
 		public bool ShowCreateShortcut
 		{
 			get => UserSettingsService.GeneralSettingsService.ShowCreateShortcut;

src/Files.App/Views/Settings/GeneralPage.xaml

@@ -304,6 +304,14 @@
 								Style="{StaticResource RightAlignedToggleSwitchStyle}" />
 						</local:SettingsBlockControl>
 
+						<!--  Create alternate data stream  -->
+						<local:SettingsBlockControl Title="{helpers:ResourceString Name=ShowCreateAlternateDataStream}" HorizontalAlignment="Stretch">
+							<ToggleSwitch
+								AutomationProperties.Name="{helpers:ResourceString Name=ShowCreateAlternateDataStream}"
+								IsOn="{x:Bind ViewModel.ShowCreateAlternateDataStream, Mode=TwoWay}"
+								Style="{StaticResource RightAlignedToggleSwitchStyle}" />
+						</local:SettingsBlockControl>
+
 						<!--  Create shortcut  -->
 						<local:SettingsBlockControl Title="{helpers:ResourceString Name=ShowCreateShortcut}" HorizontalAlignment="Stretch">
 							<ToggleSwitch