Update

Author: 0x5bfa

src/Files.App.Controls/BreadcrumbBar/BreadcrumbBar.Properties.cs

@@ -2,13 +2,6 @@
 // Licensed under the MIT License.
 
 using CommunityToolkit.WinUI;
-using Microsoft.UI;
-using Microsoft.UI.Xaml;
-using Microsoft.UI.Xaml.Controls;
-using Microsoft.UI.Xaml.Input;
-using Microsoft.UI.Xaml.Markup;
-using Microsoft.UI.Xaml.Media;
-using Microsoft.UI.Xaml.Shapes;
 
 namespace Files.App.Controls
 {
@@ -22,13 +15,5 @@ public partial class BreadcrumbBar : Control
 
 		[GeneratedDependencyProperty]
 		public partial FrameworkElement? RootItem { get; set; }
-
-		partial void OnItemsSourceChanged(object? newValue)
-		{
-		}
-
-		partial void OnItemTemplateChanged(object? newValue)
-		{
-		}
 	}
 }

src/Files.App.Controls/BreadcrumbBar/BreadcrumbBar.cs

@@ -1,7 +1,6 @@
 // Copyright (c) Files Community
 // Licensed under the MIT License.
 
-using CommunityToolkit.WinUI;
 using Microsoft.UI;
 using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
@@ -57,28 +56,39 @@ protected override void OnApplyTemplate()
 			_rootBreadcrumbBarItem.SetOwner(this);
 			_itemsRepeater.Layout = _itemsRepeaterLayout;
 
+			Loaded += BreadcrumbBar_Loaded;
 			_itemsRepeater.ElementPrepared += ItemsRepeater_ElementPrepared;
 
 			base.OnApplyTemplate();
 		}
 
-		internal void RaiseItemClickedEvent(BreadcrumbBarItem item)
+		private void BreadcrumbBar_Loaded(object sender, RoutedEventArgs e)
+		{
+		}
+
+		internal protected virtual void RaiseItemClickedEvent(BreadcrumbBarItem item)
 		{
 			var index = _itemsRepeater?.GetElementIndex(item) ?? throw new ArgumentNullException($"{_itemsRepeater} is null.");
 			var eventArgs = new BreadcrumbBarItemClickedEventArgs(item, index, item == _rootBreadcrumbBarItem);
 			ItemClicked?.Invoke(this, eventArgs);
 		}
 
-		internal void RaiseItemDropDownFlyoutOpening(BreadcrumbBarItem item, MenuFlyout flyout)
+		internal protected virtual void RaiseItemDropDownFlyoutOpening(BreadcrumbBarItem item, MenuFlyout flyout)
 		{
 			var index = _itemsRepeater?.GetElementIndex(item) ?? throw new ArgumentNullException($"{_itemsRepeater} is null.");
 			ItemDropDownFlyoutOpening?.Invoke(this, new(flyout, item, index, item == _rootBreadcrumbBarItem));
 		}
 
-		internal void RaiseItemDropDownFlyoutClosed(BreadcrumbBarItem item, MenuFlyout flyout)
+		internal protected virtual void RaiseItemDropDownFlyoutClosed(BreadcrumbBarItem item, MenuFlyout flyout)
 		{
 			var index = _itemsRepeater?.GetElementIndex(item) ?? throw new ArgumentNullException($"{_itemsRepeater} is null.");
 			ItemDropDownFlyoutClosed?.Invoke(this, new(flyout, item, index, item == _rootBreadcrumbBarItem));
 		}
+
+		internal protected virtual void OnLayoutUpdated()
+		{
+			if (_itemsRepeater is null)
+				return;
+		}
 	}
 }

src/Files.App.Controls/BreadcrumbBar/BreadcrumbBarItem.Properties.cs

@@ -2,13 +2,6 @@
 // Licensed under the MIT License.
 
 using CommunityToolkit.WinUI;
-using Microsoft.UI;
-using Microsoft.UI.Xaml;
-using Microsoft.UI.Xaml.Controls;
-using Microsoft.UI.Xaml.Input;
-using Microsoft.UI.Xaml.Markup;
-using Microsoft.UI.Xaml.Media;
-using Microsoft.UI.Xaml.Shapes;
 
 namespace Files.App.Controls
 {

src/Files.App.Controls/BreadcrumbBar/BreadcrumbBarLayout.cs

@@ -1,27 +1,27 @@
 // Copyright (c) Files Community
 // Licensed under the MIT License.
 
-using Microsoft.UI;
-using Microsoft.UI.Xaml;
-using Microsoft.UI.Xaml.Controls;
-using Microsoft.UI.Xaml.Input;
-using Microsoft.UI.Xaml.Markup;
-using Microsoft.UI.Xaml.Media;
-using Microsoft.UI.Xaml.Shapes;
 using Windows.Foundation;
 
 namespace Files.App.Controls
 {
+	/// <summary>
+	/// Handles layout of <see cref="BreadcrumbBar"/>, collapsing items into an ellipsis button when necessary.
+	/// </summary>
 	public partial class BreadcrumbBarLayout : NonVirtualizingLayout
 	{
+		// Fields
+
 		private Size _availableSize;
 		private BreadcrumbBarItem? _ellipsisButton = null;
 		private WeakReference<BreadcrumbBar>? _ownerRef;
 		private double _spacing = 0d;
 
-		private bool _ellipsisIsRendered;
-		private int _indexAfterEllipsis;
-		private int _visibleItemsCount;
+		// Properties
+
+		public bool EllipsisIsRendered { get; private set; }
+		public int IndexAfterEllipsis { get; private set; }
+		public int VisibleItemsCount { get; private set; }
 
 		public BreadcrumbBarLayout(BreadcrumbBar breadcrumb, double spacing)
 		{
@@ -50,7 +50,7 @@ protected override Size MeasureOverride(NonVirtualizingLayoutContext context, Si
 				_ellipsisButton ??= context.Children[0] as BreadcrumbBarItem;
 
 			// Sets the ellipsis item's visibility based on whether the items are overflowing
-			_ellipsisIsRendered = accumulatedSize.Width > availableSize.Width;
+			EllipsisIsRendered = accumulatedSize.Width > availableSize.Width;
 
 			return accumulatedSize;
 		}
@@ -59,20 +59,22 @@ protected override Size ArrangeOverride(NonVirtualizingLayoutContext context, Si
 		{
 			double accumulatedWidths = 0d;
 
-			_indexAfterEllipsis = GetFirstIndexToRender(context);
+			IndexAfterEllipsis = GetFirstIndexToRender(context);
 
 			// Go through all items and arrange them
 			int index = 0;
 			foreach (var item in context.Children)
 			{
 				if (item is BreadcrumbBarItem breadcrumbItem)
 				{
-					if (index < _indexAfterEllipsis)
+					if (index < IndexAfterEllipsis)
 					{
+						// Collapse
 						breadcrumbItem.Arrange(new Rect(0, 0, 0, 0));
 					}
 					else
 					{
+						// Arrange normally
 						breadcrumbItem.Arrange(new Rect(accumulatedWidths, 0, breadcrumbItem.DesiredSize.Width, breadcrumbItem.DesiredSize.Height));
 
 						accumulatedWidths += breadcrumbItem.DesiredSize.Width;
@@ -83,6 +85,9 @@ protected override Size ArrangeOverride(NonVirtualizingLayoutContext context, Si
 				}
 			}
 
+			if (_ownerRef?.TryGetTarget(out var breadcrumbBar) ?? false)
+				breadcrumbBar.OnLayoutUpdated();
+
 			return finalSize;
 		}