[Windows] Fix wrong Layout from hidden CollectionView

[jsuarezruiz]

Description of Change

Fix wrong Layout from hidden CollectionView.

Issues Fixed

Fixes #17400
Fixes #18395

[jsuarezruiz]

With an invisible CollectionView, the _wrapGrid will be null (VisualTreeHelper.GetChildrenCount will return 0) and will not apply the correct sizes.

[PureWeen]

not sure to what extent this matters, but it looks like you can subscribe to ChoosingItemContainer and call FindItemsWrapGrid from there.

It just feels a bit weird to set the size information of the WrappedGrid inside the ArrangeOverride call.

Thoughts on just calling it from there?

public FormsGridView()
{
	// Using the full style for this control, because for some reason on 16299 we can't set the ControlTemplate
	// (it just fails silently saying it can't find the resource key)
	DefaultStyleKey = typeof(FormsGridView);

	RegisterPropertyChangedCallback(ItemsPanelProperty, ItemsPanelChanged);

	this.ChoosingItemContainer += FormsGridView_ChoosingItemContainer;
}

private void FormsGridView_ChoosingItemContainer(ListViewBase sender, ChoosingItemContainerEventArgs args)
{
	if (_wrapGrid is not null)
		FindItemsWrapGrid();
}

And then even for good measure

protected override global::Windows.Foundation.Size MeasureOverride(global::Windows.Foundation.Size availableSize)
{
	var result =  base.MeasureOverride(availableSize); // it looks like the grid comes into existence here.

	FindItemsWrapGrid();

	return result;
}

I also wonder if we should null at the grid and unsubscribe when the orientation is changed.

The Orientation applies a different template so the wrapgrid is going to change.
But maybe this GridView is recreated when the orientation gets changed?

		public Orientation Orientation
		{
			get => _orientation;
			set
			{
				_orientation = value;
				if (_orientation == Orientation.Horizontal)
				{
					ItemsPanel = (ItemsPanelTemplate)UWPApp.Current.Resources["HorizontalGridItemsPanel"];
					ScrollViewer.SetHorizontalScrollMode(this, WScrollMode.Auto);
					ScrollViewer.SetHorizontalScrollBarVisibility(this, UWPControls.ScrollBarVisibility.Auto);
				}
				else
				{
					ItemsPanel = (ItemsPanelTemplate)UWPApp.Current.Resources["VerticalGridItemsPanel"];
				}
			}
		}

[PureWeen]

Currently this PR is targeting main (SR1) with a GA milestone.
Can you please update the Milestone to SR1 or update the targeted branch to net8.0.

[jsuarezruiz]

Currently this PR is targeting main (SR1) with a GA milestone. Can you please update the Milestone to SR1 or update the targeted branch to net8.0.

Retarget to net8.0

[samhouts]

@jsuarezruiz Failing tests?

[jsuarezruiz]

@jsuarezruiz Failing tests?

Updated the snapshop (from CI) from the golden test.

[PureWeen]

not sure to what extent this matters, but it looks like you can subscribe to ChoosingItemContainer and call FindItemsWrapGrid from there.

It just feels a bit weird to set the size information of the WrappedGrid inside the ArrangeOverride call.

Thoughts on just calling it from there?

public FormsGridView()
{
	// Using the full style for this control, because for some reason on 16299 we can't set the ControlTemplate
	// (it just fails silently saying it can't find the resource key)
	DefaultStyleKey = typeof(FormsGridView);

	RegisterPropertyChangedCallback(ItemsPanelProperty, ItemsPanelChanged);

	this.ChoosingItemContainer += FormsGridView_ChoosingItemContainer;
}

private void FormsGridView_ChoosingItemContainer(ListViewBase sender, ChoosingItemContainerEventArgs args)
{
	if (_wrapGrid is not null)
		FindItemsWrapGrid();
}

And then even for good measure

protected override global::Windows.Foundation.Size MeasureOverride(global::Windows.Foundation.Size availableSize)
{
	var result =  base.MeasureOverride(availableSize); // it looks like the grid comes into existence here.

	FindItemsWrapGrid();

	return result;
}

I also wonder if we should null at the grid and unsubscribe when the orientation is changed.

The Orientation applies a different template so the wrapgrid is going to change.
But maybe this GridView is recreated when the orientation gets changed?

		public Orientation Orientation
		{
			get => _orientation;
			set
			{
				_orientation = value;
				if (_orientation == Orientation.Horizontal)
				{
					ItemsPanel = (ItemsPanelTemplate)UWPApp.Current.Resources["HorizontalGridItemsPanel"];
					ScrollViewer.SetHorizontalScrollMode(this, WScrollMode.Auto);
					ScrollViewer.SetHorizontalScrollBarVisibility(this, UWPControls.ScrollBarVisibility.Auto);
				}
				else
				{
					ItemsPanel = (ItemsPanelTemplate)UWPApp.Current.Resources["VerticalGridItemsPanel"];
				}
			}
		}

[ghost]

Hi @jsuarezruiz. We have added the "s/pr-needs-author-input" label to this issue, which indicates that we have an open question/action for you before we can take further action. This PRwill be closed automatically in 14 days if we do not hear back from you by then - please feel free to re-open it if you come back to this PR after that time.

[PureWeen]

/backport to release/8.0.1xx-rc2.1

[github-actions]

Started backporting to release/8.0.1xx-rc2.1: https://github.com/dotnet/maui/actions/runs/6576174770