[Preview 4] AV(Null) in SystemNavigationManager.GetForCurrentView()

[huoyaoyuan]

Describe the bug
Access violation to location 0x00000000. This should be a null pointer exception.

Steps to reproduce the bug

Steps to reproduce the behavior:

1. Create a blank WinUI 3 desktop app for Preview 4. Verifies that blank app works.
2. Install Microsoft.Toolkit.Uwp.UI.Controls 8.0.0-preview4 from their feed.
3. Add a blank MasterDetailsView to main window.
4. Exception thrown when the MasterDetailsView is loaded.

Expected behavior
Shows without exception.

Version Info

NuGet package version:

Microsoft.WinUI 3.0.0-preview4.210210.4
Not seeing in preview3 or preview2.

Windows app type:

UWP	Win32
	Yes

Windows 10 version	Saw the problem?
Insider Build (xxxxx)
October 2020 Update (19042)	Yes
May 2020 Update (19041)
November 2019 Update (18363)
May 2019 Update (18362)
October 2018 Update (17763)
April 2018 Update (17134)
Fall Creators Update (16299)
Creators Update (15063)

Device form factor	Saw the problem?
Desktop	Yes
Xbox
Surface Hub
IoT

Additional context
Stack trace:

 	CoreUIComponents.dll!Microsoft::WRL::ComPtr<Windows::UI::Core::ICoreWindow>::As<ICoreWindowInterop>()	未知
 	CoreUIComponents.dll!Windows::UI::Core::SystemNavigationManagerStatics::GetForCurrentView()	未知
 	[托管到本机的转换]	
 	Microsoft.Windows.SDK.NET.dll!ABI.Windows.UI.Core.ISystemNavigationManagerStatics.Windows.UI.Core.ISystemNavigationManagerStatics.GetForCurrentView()	未知
 	Microsoft.Windows.SDK.NET.dll!Windows.UI.Core.SystemNavigationManager.GetForCurrentView()	未知
 	Microsoft.Toolkit.Uwp.UI.Controls.dll!Microsoft.Toolkit.Uwp.UI.Controls.MasterDetailsView.OnLoaded(object sender, Microsoft.UI.Xaml.RoutedEventArgs e)	未知

WCTK side may be updated to guard for using it. But WinUI side should gracefully return null or something other than crash with null AV.

[huoyaoyuan]

For preview 3, the same exception is thrown before window shown, and successes after shown.
For preview 4, the exception is still thrown after window shown.

If the API is not meant to be called in WinUI desktop, please tell WCTK to remove the call to it.

[StephenLPeters]

@Austin-Lamb FYI, @michael-hawker with Winui3 preview 4 GetForCurrentView is no long valid to call on Desktop applications.

[huoyaoyuan]

Can the API errors more gracefully?

[michael-hawker]

@StephenLPeters thanks, yeah I thought we had replaced all those already. @azchohfi did we miss this one in the past, or is this a new case for Preview 4 that we didn't catch?

@huoyaoyuan thanks for reporting an issue, we'll take a look. We've been a bit focused on clamping down our main 7.0 release, but we'll be doing a bit more vetting of the WinUI 3 versions of controls in March. We have a lot of controls, and we haven't onboarded everything into our integrated tests yet, and are still working on getting those to run on top of WinUI 3 as well.

[huoyaoyuan]

This is currently blocking MasterDetailsView totally.

[MikeHillberg]

Can the API errors more gracefully?

Unfortunately I'm not sure if there's anything we can do to make them return null or some such. A way to anticipate it is to check the Window.Current property, which will be null in a Desktop app, which is where the GetForCurrentView APIs won't work.

[mvegaca]

Hello, I'm Martin from Windows Template Studio Team.

I'm updating WinUI Templates to WinUI Preview 4 and I'm also having the same Issue

Exception thrown at 0x67D178BE (CoreUIComponents.dll) in MasterDetailIssueApp.exe: 0xC0000005: Access violation reading location 0x00000000.

Adding minimal repro app.
MasterDetailIssueApp.zip

I hope it helps 👍

[MikeHillberg]

I believe SystemNavigationManager only raises its BackRequested event for UWP apps. So best to just ignore this (don't try to retrieve it) on Desktop.

[azchohfi]

@azchohfi did we miss this one in the past, or is this a new case for Preview 4 that we didn't catch?

New case in preview4, which we missed for this release.

[huoyaoyuan]

Hello, the same issue is blocking ListDetailView (renamed from MasterDetailsView) again, in WinUI/WAS 1.0.0-preview3. @michael-hawker @Austin-Lamb