ListDetailsView not working with WinUI3/WindowsAppSDK 1.0.0-preview3

[huoyaoyuan]

Describe the bug

ListDetailsView causes hard crash in normal usage.

• Is this bug a regression in the toolkit? If so, what toolkit version did you last see it work:
  7.0.1

Steps to Reproduce

• Can this be reproduced in the Sample App? (Either in a sample as-is or with new XAML pasted in the editor.) If so, please provide custom XAML or steps to reproduce. If not, let us know why it can't be reproduced (e.g. more complex setup, environment, dependencies, etc...)

Steps to reproduce the behavior:

1. Create a WinUI3/WAS project, install toolkit 7.1.1-preview3
2. Add a ListDetailsView, set ListPaneWidth and some content
3. if ListPaneWidth set in xaml, it will fail with XamlParseException which wrappes NullReferenceException
   4. When moving mouse over the control. it will fail with not being able to load reveal brush
   Edit: I used reveal brush in my custom style. It's not caused by the control itself.

Environment

NuGet Package(s):
CommunityToolkit.WinUI.UI.Controls.Layout
Microsoft.WindowsAppSDK 1.0.0-preview3

Package Version(s):
7.1.1-preview3

Windows 10 Build Number:

• Fall Creators Update (16299)
• April 2018 Update (17134)
• October 2018 Update (17763)
• May 2019 Update (18362)
• May 2020 Update (19043)
• Insider Build ({build_number})

App min and target version:

• Fall Creators Update (16299)
• April 2018 Update (17134)
• October 2018 Update (17763)
• May 2019 Update (18362)
• May 2020 Update (19041)
• Insider Build ({build_number})

Device form factor:

• Desktop
• Xbox
• Surface Hub
• IoT

Visual Studio version:

• 2017 (15.{minor_version})
• 2019 (16.{minor_version})
• 2022 (17.{minor_version})

Additional context

This could be a issue of WinUI side, but we should be aware of them here.

[ghost]

Hello huoyaoyuan, thank you for opening an issue with us!

I have automatically added a "needs triage" label to help get things started. Our team will analyze and investigate the issue, and escalate it to the relevant team if possible. Other community members may also look into the issue and provide feedback 🙌

[huoyaoyuan]

The call stack is native SystemNavigationManager::GetForCurrentView, so this is microsoft/microsoft-ui-xaml#4174 again.

[michael-hawker]

Thanks @huoyaoyuan I think we missed from the original WinUI discussion that there was code we needed to update here too. Thanks for filing an issue.

@azchohfi looks like we missed how best to convert these APIs here:

WindowsCommunityToolkit/CommunityToolkit.WinUI.UI.Controls.Layout/ListDetailsView/ListDetailsView.cs

Lines 173 to 176 in 82e2bbb

	if (Window.Current != null)
	{
	SystemNavigationManager.GetForCurrentView().BackRequested += OnBackRequested;
	}

WindowsCommunityToolkit/CommunityToolkit.WinUI.UI.Controls.Layout/ListDetailsView/ListDetailsView.cs

Lines 196 to 199 in 82e2bbb

	if (Window.Current != null)
	{
	SystemNavigationManager.GetForCurrentView().BackRequested -= OnBackRequested;
	}

According to the docs this isn't a WinUI 3 API at all. We used it here to synchronize the behavior of the ListDetailsView to the main app back button. Since that concept doesn't exist, I think we just remove this code entirely in our WinUI 3 world, right?

I think our original hope was that Window.Current was going to be a guard for this, or am I mis-remembering?

[huoyaoyuan]

Since that concept doesn't exist, I think we just remove this code entirely in our WinUI 3 world, right?

How about WinUI 3 with UWP? On Win32 I think we can remove it.

[michael-hawker]

@huoyaoyuan sorry are you creating a WinUI 3 UWP project? We only support WinUI 3 Desktop projects with the Toolkit.

[michael-hawker]

Ah, we found some unguarded cases in https://github.com/CommunityToolkit/WindowsCommunityToolkit/blob/main/Microsoft.Toolkit.Uwp.UI.Controls.Layout/ListDetailsView/ListDetailsView.BackButton.cs, so those may be it as well. We're adding guards :)

[huoyaoyuan]

@michael-hawker No, just in case if you are missing that scenario.

[michael-hawker]

@huoyaoyuan we just shipped an update which we think will address the issue?https://github.com/CommunityToolkit/WindowsCommunityToolkit/releases/tag/winui-7.1.1-preview3.1

Please let us know, thanks!

[huoyaoyuan]

@michael-hawker Yes it works.

However, I discovered that ListPaneWidth has a another issue. It throws NRE (0x80004003 : 'Object reference not set to an instance of an object.') if I set it in xaml. It works correctly if I set it later in xaml hot reload.

This is not so critical and I can wait for next version.

[suchja]

I do have the same problem with ListPaneWidth. Unfortunately it comes out of some template and I can't find any workaround for this:

As far as I can see there is no custom template I supply which changes the ListPaneWidth. So I'm currently not able to use the ListDetailView. I'm using winui-7.1.1-preview3.1 and tested with .NET 5.0 as well as .NET 6.0.

[DanyaSWorlD]

Have same isuue. Any workarounds? I'm using version 7.1.2 and .NET 6.0

[michael-hawker]

Was able to reproduce this in UWP as well, so not specific to WinUI 3. It was overlooked with the change to TwoPaneView for this component in PR #3768, so setting ListPaneWidth before loading is just broken due to lack of null check in OnListPaneWidthChanged, fix should be:

        private void OnListPaneWidthChanged()
        {
            if (_twoPaneView != null)
            {
                _twoPaneView.Pane1Length = new GridLength(ListPaneWidth);
            }
        }

[LalithaNadimpalli]

Hi, Thank you for raising the Issue, Created a PR with the suggested changes