Fix for CollectionView with GridItemsLayout (Span=1) doesn't adapt to window width reduction on Windows platform by praveenkumarkarunanithi · Pull Request #31038 · dotnet/maui

praveenkumarkarunanithi · 2025-08-06T11:37:08Z

Root Cause

In the single-column case (Span = 1), setting the ItemWidth on the native UWP ItemsWrapGrid to match the full container width causes the layout system to treat the item size as fixed. As a result, no size change is detected during window resizing, and the SizeChanged event does not fire. In contrast, when Span > 1, the ItemWidth is smaller than the container, allowing the layout to reflow and correctly trigger SizeChanged.
This behavior aligns with UWP documentation, which states that SizeChanged occurs only when ActualWidth or ActualHeight changes, and does not fire “if the position of the object within a parent container changes, but not the size.”

Description of Change

The fix updates the UpdateItemSize method in FormsGridView.cs to conditionally skip setting the ItemWidth when the layout has only one column (Span == 1). In this case, ItemWidth remains at its default value, allowing the native UWP ItemsWrapGrid to use its built-in Auto layout behavior. This ensures that the control remains responsive and correctly handles window size changes.

Issues Fixed

Fixes #23702
#26083

Tested the behaviour in the following platforms

Android
Windows
iOS
Mac

Screenshots

Before Issue Fix	After Issue Fix

dotnet-policy-service · 2025-08-06T11:37:27Z

Hey there @@praveenkumarkarunanithi! Thank you so much for your PR! Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

Copilot

Pull Request Overview

This PR fixes a window resizing issue with CollectionView using GridItemsLayout on Windows where single-column layouts (Span=1) don't properly adapt when the window width is reduced. The root cause is that setting ItemWidth to the full container width prevents the UWP SizeChanged event from firing during resize operations.

Conditionally skips setting ItemWidth for single-column layouts (Span=1) to allow native Auto layout behavior
Adds comprehensive UI test coverage to validate the fix behavior
Maintains existing functionality for multi-column layouts (Span>1)

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
`src/Controls/src/Core/Platform/Windows/CollectionView/FormsGridView.cs`	Core fix that conditionally clears ItemWidth for single-column GridItemsLayout
`src/Controls/tests/TestCases.HostApp/Issues/Issue23702.cs`	UI test page demonstrating the CollectionView resize behavior
`src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue23702.cs`	Automated test validating that items resize correctly when width decreases

Comments suppressed due to low confidence (1)

Copilot · 2025-08-08T11:06:22Z

src/Controls/tests/TestCases.HostApp/Issues/Issue23702.cs

+				label.PropertyChanged += (sender, e) =>
+				{
+					if (e.PropertyName == "Width" && sender is Label sl && sl.Width > 0)
+					{
+						_widthLabel.Text = Math.Round(sl.Width).ToString();
+					}
+				};


PropertyChanged event handler is attached inside the DataTemplate factory method, which means a new handler is created for every item in the collection. This could lead to memory leaks if items are recycled. Consider using a WeakEventManager or detaching the handler when appropriate.

Suggested change

label.PropertyChanged += (sender, e) =>

{

if (e.PropertyName == "Width" && sender is Label sl && sl.Width > 0)

{

_widthLabel.Text = Math.Round(sl.Width).ToString();

}

};

WeakEventManager<PropertyChangedEventArgs>.AddHandler(label, nameof(label.PropertyChanged), (sender, e) =>

{

if (e.PropertyName == "Width" && sender is Label sl && sl.Width > 0)

{

_widthLabel.Text = Math.Round(sl.Width).ToString();

}

});

jsuarezruiz · 2025-09-01T11:15:18Z

/azp run MAUI-UITests-public

azure-pipelines · 2025-09-01T11:15:30Z

Azure Pipelines successfully started running 1 pipeline(s).

jsuarezruiz · 2025-09-08T14:19:47Z

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue26083.cs

+
+		[Test]
+		[Category(UITestCategories.CollectionView)]
+		public void ItemsWrapGridShouldUpdateBasedOnCollectionViewSize()


Pending snapshot on Mac and Windows:
ItemsWrapGridShouldUpdateBasedOnCollectionViewSize

Could you commit the images?

@jsuarezruiz updated the images for UI test from CI.

jsuarezruiz · 2025-09-16T06:40:55Z

/azp run MAUI-UITests-public

azure-pipelines · 2025-09-16T06:41:09Z

Azure Pipelines successfully started running 1 pipeline(s).

alex3696 · 2025-10-21T01:20:29Z

Are there any chances that this error will be fixed in maui 9? I've been waiting for a long time...

… window width reduction on Windows platform (#31038) * fix update. * updated test case * optimised test case * Update FormsGridView.cs * updated test case for 26083 * updated UI test images from CI * updated UI test from CI-2

praveenkumarkarunanithi added 3 commits July 31, 2025 10:23

fix update.

ed93a97

updated test case

9bd86e1

optimised test case

a5b3450

dotnet-policy-service bot added the community ✨ Community Contribution label Aug 6, 2025

praveenkumarkarunanithi changed the title ~~Fix 23702~~ Fix for CollectionView with GridItemsLayout (Span=1) doesn't adapt to window width reduction on Windows platform Aug 6, 2025

dotnet-policy-service bot added the partner/syncfusion Issues / PR's with Syncfusion collaboration label Aug 6, 2025

Update FormsGridView.cs

ea4280f

praveenkumarkarunanithi marked this pull request as ready for review August 8, 2025 11:05

Copilot AI review requested due to automatic review settings August 8, 2025 11:05

praveenkumarkarunanithi requested a review from a team as a code owner August 8, 2025 11:05

praveenkumarkarunanithi requested review from StephaneDelcroix and jsuarezruiz August 8, 2025 11:05

Copilot AI reviewed Aug 8, 2025

View reviewed changes

updated test case for 26083

7162364

BagavathiPerumal mentioned this pull request Aug 11, 2025

[Windows] Fix for UI not updating GridItemsLayout when Span becomes 1. #26370

Closed

4 tasks

jsuarezruiz suggested changes Sep 8, 2025

View reviewed changes

praveenkumarkarunanithi added 2 commits September 9, 2025 16:59

updated UI test images from CI

64410c2

updated UI test from CI-2

45131e1

jsuarezruiz added the area-controls-collectionview CollectionView, CarouselView, IndicatorView label Oct 24, 2025

jsuarezruiz approved these changes Oct 24, 2025

View reviewed changes

PureWeen changed the base branch from main to inflight/current October 31, 2025 20:30

PureWeen merged commit fdb9206 into dotnet:inflight/current Oct 31, 2025
78 of 79 checks passed

PureWeen added this to the .NET 10.0 SR1 milestone Nov 7, 2025

PureWeen added this to MAUI SDK Ongoing Nov 7, 2025

github-project-automation bot moved this to Todo in MAUI SDK Ongoing Nov 7, 2025

github-actions bot locked and limited conversation to collaborators Dec 8, 2025

PureWeen moved this from Todo to Done in MAUI SDK Ongoing Dec 30, 2025

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Fix for CollectionView with GridItemsLayout (Span=1) doesn't adapt to window width reduction on Windows platform#31038

Fix for CollectionView with GridItemsLayout (Span=1) doesn't adapt to window width reduction on Windows platform#31038
PureWeen merged 7 commits intodotnet:inflight/currentfrom
praveenkumarkarunanithi:fix-23702

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Root Cause

Description of Change

Issues Fixed

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praveenkumarkarunanithi commented Aug 6, 2025 •

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