Fix VerticalGrid column shrinking issue in Windows CollectionView

Co-authored-by: NanthiniMahalingam <[email protected]>

Author: Copilot

src/Controls/src/Core/Platform/Windows/CollectionView/FormsGridView.cs

@@ -115,11 +115,11 @@ void UpdateItemSize()
 
 			if (_orientation == Orientation.Horizontal)
 			{
-				_wrapGrid.ItemHeight = Math.Floor(_wrapGrid.ActualHeight / Span);
+				_wrapGrid.ItemHeight = Math.Round(_wrapGrid.ActualHeight / Span);
 			}
 			else
 			{
-				_wrapGrid.ItemWidth = Math.Floor(_wrapGrid.ActualWidth / Span);
+				_wrapGrid.ItemWidth = Math.Round(_wrapGrid.ActualWidth / Span);
 			}
 		}
 

src/Controls/tests/TestCases.HostApp/Issues/IssueVerticalGridShrinking.xaml

@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             x:Class="Maui.Controls.Sample.Issues.IssueVerticalGridShrinking">
+
+    <Grid RowDefinitions="Auto,*">
+        <Label Text="VerticalGrid items should fill available width when resized" 
+               AutomationId="InstructionLabel"
+               Grid.Row="0"
+               FontSize="16"
+               Margin="10"/>
+        
+        <CollectionView x:Name="collectionView" 
+                       AutomationId="TestCollectionView"
+                       Grid.Row="1"
+                       Margin="10"
+                       BackgroundColor="LightGray"
+                       ItemsSource="{Binding Items}">
+            
+            <CollectionView.ItemsLayout>
+                <GridItemsLayout Orientation="Vertical" 
+                               Span="2" 
+                               HorizontalItemSpacing="5"
+                               VerticalItemSpacing="5"/>
+            </CollectionView.ItemsLayout>
+            
+            <CollectionView.ItemTemplate>
+                <DataTemplate>
+                    <Grid BackgroundColor="LightBlue" 
+                          Padding="10"
+                          AutomationId="ItemGrid">
+                        <Label Text="{Binding}" 
+                               FontSize="14" 
+                               HorizontalOptions="Center"
+                               VerticalOptions="Center"
+                               AutomationId="ItemLabel"/>
+                    </Grid>
+                </DataTemplate>
+            </CollectionView.ItemTemplate>
+        </CollectionView>
+    </Grid>
+
+</ContentPage>

src/Controls/tests/TestCases.HostApp/Issues/IssueVerticalGridShrinking.xaml.cs

@@ -0,0 +1,23 @@
+using System.Collections.ObjectModel;
+
+namespace Maui.Controls.Sample.Issues
+{
+	[Issue(IssueTracker.Github, 17, "VerticalGrid column in CollectionView does not shrink in Windows", PlatformAffected.Windows)]
+	public partial class IssueVerticalGridShrinking : ContentPage
+	{
+		public ObservableCollection<string> Items { get; set; }
+
+		public IssueVerticalGridShrinking()
+		{
+			InitializeComponent();
+			
+			Items = new ObservableCollection<string>();
+			for (int i = 1; i <= 20; i++)
+			{
+				Items.Add($"Item {i}");
+			}
+			
+			BindingContext = this;
+		}
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/IssueVerticalGridShrinking.cs

@@ -0,0 +1,42 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues
+{
+	public class IssueVerticalGridShrinkingUITests : _IssuesUITest
+	{
+		public IssueVerticalGridShrinkingUITests(TestDevice device)
+			: base(device)
+		{
+		}
+
+		public override string Issue => "VerticalGrid column in CollectionView does not shrink in Windows";
+
+		[Test]
+		[Category(UITestCategories.CollectionView)]
+		public void VerticalGridItemsShouldFillAvailableWidth()
+		{
+			// Wait for the CollectionView to load
+			App.WaitForElement("TestCollectionView");
+			
+			// Verify instruction label is present
+			App.WaitForElement("InstructionLabel");
+			
+			// Wait for at least one item to be loaded
+			App.WaitForElement("ItemGrid");
+			
+			// The test should verify that grid items fill the available width properly
+			// Without the fix, items would be smaller due to Math.Floor calculation
+			// With the fix, items should utilize available space better
+			
+			// This is primarily a visual test - the fix ensures items don't appear cropped
+			// or leave excessive empty space on the right when the container width
+			// doesn't divide evenly by the span count
+			
+			// For automated testing, we just verify the UI loads without exceptions
+			var items = App.QueryElements("ItemGrid");
+			Assert.That(items.Count, Is.GreaterThan(0), "CollectionView should contain grid items");
+		}
+	}
+}