Feature: Added support for resizing columns in the Columns View

src/Files.App.Controls/BladeView/BladeItem.cs

@@ -1,7 +1,12 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using CommunityToolkit.WinUI;
+using Microsoft.UI.Input;
 using Microsoft.UI.Xaml.Automation.Peers;
+using Microsoft.UI.Xaml.Input;
+using Microsoft.UI.Xaml.Media;
+using Windows.Foundation;
 
 namespace Files.App.Controls
 {
@@ -11,11 +16,18 @@
 	[TemplatePart(Name = "CloseButton", Type = typeof(Button))]
 	public partial class BladeItem : ContentControl
 	{
+		private const double MINIMUM_WIDTH = 150;
+		private const double DEFAULT_WIDTH = 300; // Default width for the blade item
+
 		private Button _closeButton;
+		private Border _bladeResizer;
+		private bool _draggingSidebarResizer;
+		private double _preManipulationSidebarWidth = 0;
+
 		/// <summary>
 		/// Initializes a new instance of the <see cref="BladeItem"/> class.
 		/// </summary>
 		public BladeItem()
 		{
 			DefaultStyleKey = typeof(BladeItem);
 		}
@@ -36,7 +48,31 @@
 
 			_closeButton.Click -= CloseButton_Click;
 			_closeButton.Click += CloseButton_Click;
+
+			_bladeResizer = GetTemplateChild("BladeResizer") as Border;
+
+			if (_bladeResizer != null)
+			{
+				_bladeResizer.ManipulationStarted -= BladeResizer_ManipulationStarted;
+				_bladeResizer.ManipulationStarted += BladeResizer_ManipulationStarted;
+
+				_bladeResizer.ManipulationDelta -= BladeResizer_ManipulationDelta;
+				_bladeResizer.ManipulationDelta += BladeResizer_ManipulationDelta;
+
+				_bladeResizer.ManipulationCompleted -= BladeResizer_ManipulationCompleted;
+				_bladeResizer.ManipulationCompleted += BladeResizer_ManipulationCompleted;
+
+				_bladeResizer.PointerEntered -= BladeResizer_PointerEntered;
+				_bladeResizer.PointerEntered += BladeResizer_PointerEntered;
+
+				_bladeResizer.PointerExited -= BladeResizer_PointerExited;
+				_bladeResizer.PointerExited += BladeResizer_PointerExited;
+
+				_bladeResizer.DoubleTapped -= BladeResizer_DoubleTapped;
+				_bladeResizer.DoubleTapped += BladeResizer_DoubleTapped;
+			}
 		}
+
 		/// <summary>
 		/// Creates AutomationPeer (<see cref="UIElement.OnCreateAutomationPeer"/>)
 		/// </summary>
@@ -50,5 +86,166 @@
 		{
 			IsOpen = false;
 		}
+
+		private void BladeResizer_ManipulationStarted(object sender, ManipulationStartedRoutedEventArgs e)
+		{
+			_draggingSidebarResizer = true;
+			_preManipulationSidebarWidth = ActualWidth;
+			VisualStateManager.GoToState(this, "ResizerPressed", true);
+			e.Handled = true;
+		}
+
+		private void BladeResizer_ManipulationDelta(object sender, ManipulationDeltaRoutedEventArgs e)
+		{
+			var newWidth = _preManipulationSidebarWidth + e.Cumulative.Translation.X;
+			if (newWidth < MINIMUM_WIDTH)
+				newWidth = MINIMUM_WIDTH;
+
+			Width = newWidth;
+			e.Handled = true;
+		}
+
+		private void BladeResizer_ManipulationCompleted(object sender, ManipulationCompletedRoutedEventArgs e)
+		{
+			_draggingSidebarResizer = false;
+			VisualStateManager.GoToState(this, "ResizerNormal", true);
+			e.Handled = true;
+		}
+
+		private void BladeResizer_DoubleTapped(object sender, DoubleTappedRoutedEventArgs e)
+		{
+			var optimalWidth = CalculateOptimalWidth();
+			if (optimalWidth > 0)
+			{
+				Width = Math.Max(optimalWidth, MINIMUM_WIDTH);
+			}
+			else
+			{
+				// Fallback to default width if calculation fails
+				Width = DEFAULT_WIDTH;
+			}
+
+			e.Handled = true;
+		}
+
+		private double CalculateOptimalWidth()
+		{
+			try
+			{
+				// Look for any ListView within this BladeItem that contains text content
+				var listView = this.FindDescendant<ListView>();
+				if (listView?.Items == null || !listView.Items.Any())
+					return 0;
+
+				// Calculate the maximum width needed by measuring text content
+				var maxTextWidth = MeasureContentWidth(listView);
+
+				// Add padding for icon, margins, and other UI elements
+				// Icon width (32) + margins (24) + padding (24) + chevron/tags (40) = 120
+				var totalPadding = 120;
+
+				return maxTextWidth + totalPadding;
+			}
+			catch (Exception)
+			{
+				return 0;
+			}
+		}
+
+		private double MeasureContentWidth(ListView listView)
+		{
+			try
+			{
+				double maxWidth = 0;
+
+				// Find all TextBlocks in the ListView using visual tree walking
+				var textBlocks = GetTextBlocksFromVisualTree(listView);
+
+				if (textBlocks.Any())
+				{
+					// Measure each TextBlock and find the widest one
+					foreach (var textBlock in textBlocks)
+					{
+						if (string.IsNullOrEmpty(textBlock.Text))
+							continue;
+
+						// Create a measuring TextBlock with the same properties
+						var measuringBlock = new TextBlock
+						{
+							Text = textBlock.Text,
+							FontSize = textBlock.FontSize,
+							FontFamily = textBlock.FontFamily,
+							FontWeight = textBlock.FontWeight,
+							FontStyle = textBlock.FontStyle
+						};
+
+						measuringBlock.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
+						maxWidth = Math.Max(maxWidth, measuringBlock.DesiredSize.Width);
+					}
+				}
+				else
+				{
+					// Fallback: estimate based on item count and average text width
+					var itemCount = listView.Items.Count;
+					if (itemCount > 0)
+					{
+						// Estimate average filename length and multiply by character width
+						var estimatedCharWidth = 8; // Approximate pixel width per character
+						var estimatedMaxLength = Math.Min(50, Math.Max(20, itemCount * 2)); // Heuristic
+						maxWidth = estimatedCharWidth * estimatedMaxLength;
+					}
+				}
+
+				return maxWidth;
+			}
+			catch (Exception)
+			{
+				// Fallback calculation
+				return 200; // Default reasonable width
+			}
+		}
+
+		private List<TextBlock> GetTextBlocksFromVisualTree(DependencyObject parent)
+		{
+			var textBlocks = new List<TextBlock>();
+
+			if (parent == null)
+				return textBlocks;
+
+			var childrenCount = VisualTreeHelper.GetChildrenCount(parent);
+			for (int i = 0; i < childrenCount; i++)
+			{
+				var child = VisualTreeHelper.GetChild(parent, i);
+
+				if (child is TextBlock textBlock)
+				{
+					textBlocks.Add(textBlock);
+				}
+
+				// Recursively search child elements
+				textBlocks.AddRange(GetTextBlocksFromVisualTree(child));
+			}
+
+			return textBlocks;
+		}
+
+		private void BladeResizer_PointerEntered(object sender, PointerRoutedEventArgs e)
+		{
+			var sidebarResizer = (FrameworkElement)sender;
+			sidebarResizer.ChangeCursor(InputSystemCursor.Create(InputSystemCursorShape.SizeWestEast));
+			VisualStateManager.GoToState(this, "ResizerPointerOver", true);
+			e.Handled = true;
+		}
+
+		private void BladeResizer_PointerExited(object sender, PointerRoutedEventArgs e)
+		{
+			if (_draggingSidebarResizer)
+				return;
+
+			var sidebarResizer = (FrameworkElement)sender;
+			sidebarResizer.ChangeCursor(InputSystemCursor.Create(InputSystemCursorShape.Arrow));
+			VisualStateManager.GoToState(this, "ResizerNormal", true);
+			e.Handled = true;
+		}
 	}
 }

src/Files.App.Controls/BladeView/BladeView.xaml

@@ -114,6 +114,18 @@
 							VerticalAlignment="Stretch"
 							Background="{TemplateBinding Background}" />
 
+						<!--  Resizer  -->
+						<Border
+							x:Name="BladeResizer"
+							Width="4"
+							HorizontalAlignment="Right"
+							VerticalAlignment="Stretch"
+							AllowFocusOnInteraction="True"
+							Background="Transparent"
+							BorderBrush="Transparent"
+							CornerRadius="2"
+							ManipulationMode="TranslateX" />
+
 						<Button
 							Name="CloseButton"
 							HorizontalAlignment="Right"
@@ -127,6 +139,33 @@
 							Style="{StaticResource ButtonRevealStyle}"
 							TabIndex="0"
 							Visibility="{TemplateBinding CloseButtonVisibility}" />
+
+						<VisualStateManager.VisualStateGroups>
+							<VisualStateGroup x:Name="ResizerStates">
+								<VisualState x:Name="ResizerNormal" />
+								<VisualState x:Name="ResizerPointerOver">
+									<Storyboard>
+										<ObjectAnimationUsingKeyFrames Storyboard.TargetName="BladeResizer" Storyboard.TargetProperty="Background">
+											<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource CardStrokeColorDefaultSolidBrush}" />
+										</ObjectAnimationUsingKeyFrames>
+										<ObjectAnimationUsingKeyFrames Storyboard.TargetName="BladeResizer" Storyboard.TargetProperty="BorderBrush">
+											<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource CardStrokeColorDefaultSolidBrush}" />
+										</ObjectAnimationUsingKeyFrames>
+									</Storyboard>
+								</VisualState>
+
+								<VisualState x:Name="ResizerPressed">
+									<Storyboard>
+										<ObjectAnimationUsingKeyFrames Storyboard.TargetName="BladeResizer" Storyboard.TargetProperty="Background">
+											<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SolidBackgroundFillColorSecondaryBrush}" />
+										</ObjectAnimationUsingKeyFrames>
+										<ObjectAnimationUsingKeyFrames Storyboard.TargetName="BladeResizer" Storyboard.TargetProperty="BorderBrush">
+											<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SolidBackgroundFillColorSecondaryBrush}" />
+										</ObjectAnimationUsingKeyFrames>
+									</Storyboard>
+								</VisualState>
+							</VisualStateGroup>
+						</VisualStateManager.VisualStateGroups>
 					</Grid>
 				</ControlTemplate>
 			</Setter.Value>