Crash after upgrade on iOS No parameterless constructor defined for type 'CommunityToolkit.Maui.Behaviors.StatusBarBehavior

[vchelaru]

I have upgraded to the latest version of community toolkit:

<PackageReference Include="CommunityToolkit.Maui" Version="11.2.0" />

This runs fine on Android, but on iOS I get:

Microsoft.Maui.Controls.Xaml.XamlParseException: 'Position 20:10. No parameterless constructor defined for type 'CommunityToolkit.Maui.Behaviors.StatusBarBehavior'.'

This is my xaml:

xmlns:toolkit="http://schemas.microsoft.com/dotnet/2022/maui/toolkit"
...
<ContentPage.Behaviors>
    <toolkit:StatusBarBehavior x:Name="StatusBar" StatusBarStyle="LightContent" />
</ContentPage.Behaviors>

As explained on the release notes:

1. I have installed .NET SDK v9.0.203 (docs say .202, is 203 okay?)
   
2. I have Xcode 16.2 installed on my mac
3. I am using Visual Studio 17.13.6
   
4. I have added a global.json with the text indicated (again it's on .202 not .203)
   I'm not sure if I need to run the .NET Maui workload since I am using the latest version of Visual Studio.

When I run my app on my iPhone, I get my app's splash screen but when it goes to the main page where my StatusBarBehavior is added, I get this exception:

Microsoft.Maui.Controls.Xaml.XamlParseException: 'Position 20:10. No parameterless constructor defined for type 'CommunityToolkit.Maui.Behaviors.StatusBarBehavior'.'

"   at Microsoft.Maui.Controls.Xaml.CreateValuesVisitor.Visit(ElementNode node, INode parentNode)\n   at Microsoft.Maui.Controls.Xaml.ElementNode.Accept(IXamlNodeVisitor visitor, INode parentNode)\n   at Microsoft.Maui.Controls.Xaml.RootNode.Accept(IXamlNodeVisitor visitor, INode parentNode)\n   at Microsoft.Maui.Controls.Xaml.XamlLoader.Visit(RootNode rootnode, HydrationContext visitorContext, Boolean useDesignProperties)\n   at Microsoft.Maui.Controls.Xaml.XamlLoader.Load(Object view, String xaml, Assembly rootAssembly, Boolean useDesignProperties)\n   at Microsoft.Maui.Controls.Xaml.XamlLoader.Load(Object view, String xaml, Boolean useDesignProperties)\n   at Microsoft.Maui.Controls.Xaml.XamlLoader.Load(Object view, Type callingType)\n   at Microsoft.Maui.Controls.Xaml.Extensions.LoadFromXaml[MainPage](MainPage view, Type callingType)\n   at LiveTulaMobile.Pages.MainPage.InitializeComponent() in C:\\Tula\\LiveTulaMobile\\obj\\Debug\\net9.0-ios\\Microsoft.Maui.Controls.SourceGen\\Microsoft.Maui.Controls.SourceGen.CodeBehindGenerator\\Pages_Home_MainPage.xaml.sg.cs:line 51\n   at LiveTulaMobile.Pages.MainPage..ctor(MainPageViewModel viewModel, IPendoService pendoService) in C:\\Tula\\LiveTulaMobile\\Pages\\Home\\MainPage.xaml.cs:line 22\n   at System.Object.InvokeStub_MainPage..ctor(Object , Span`1 )\n   at System.Reflection.MethodBaseInvoker.InvokeWithFewArgs(Object , BindingFlags , Binder , Object[] , CultureInfo )\n   at System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags , Binder , Object[] , CultureInfo )\n   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite , RuntimeResolverContext )\n   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2[[Microsoft.Extensions.DependencyInjection.ServiceLookup.RuntimeResolverContext, Microsoft.Extensions.DependencyInjection, Version=9.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60],[System.Object, System.Private.CoreLib, Version=9.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].VisitCallSiteMain(ServiceCallSite , RuntimeResolverContext )\n   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitRootCache(ServiceCallSite , RuntimeResolverContext )\n   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2[[Microsoft.Extensions.DependencyInjection.ServiceLookup.RuntimeResolverContext, Microsoft.Extensions.DependencyInjection, Version=9.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60],[System.Object, System.Private.CoreLib, Version=9.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].VisitCallSite(ServiceCallSite callSite, RuntimeResolverContext argument)\n   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite , ServiceProviderEngineScope )\n   at Microsoft.Extensions.DependencyInjection.ServiceProvider.CreateServiceAccessor(ServiceIdentifier serviceIdentifier)\n   at System.Collections.Concurrent.ConcurrentDictionary`2[[Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceIdentifier, Microsoft.Extensions.DependencyInjection, Version=9.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60],[Microsoft.Extensions.DependencyInjection.ServiceProvider.ServiceAccessor, Microsoft.Extensions.DependencyInjection, Version=9.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60]].GetOrAdd(ServiceIdentifier , Func`2 )\n   at Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService(ServiceIdentifier , ServiceProviderEngineScope )\n   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type )\n   at Microsoft.Maui.MauiContext.WrappedServiceProvider.GetService(Type serviceType)\n   at Microsoft.Maui.Controls.ShellContent.<>c__DisplayClass20_0.<Microsoft.Maui.Controls.IShellContentController.GetOrCreateContent>b__0()\n   at Microsoft.Maui.Controls.ElementTemplate.CreateContent()\n   at Microsoft.Maui.Controls.Internals.DataTemplateExtensions.CreateContent(DataTemplate self, Object item, BindableObject container)\n   at Microsoft.Maui.Controls.ShellContent.Microsoft.Maui.Controls.IShellContentController.GetOrCreateContent()\n   at Microsoft.Maui.Controls.Platform.Compatibility.ShellSectionRootRenderer.LoadRenderers()\n   at Microsoft.Maui.Controls.Platform.Compatibility.ShellSectionRootRenderer.ViewDidLoad()\n   at Microsoft.Maui.Controls.Platform.Compatibility.ShellSectionRootRenderer.__Registrar_Callbacks__.callback_522_Microsoft_Maui_Controls_Platform_Compatibility_ShellSectionRootRenderer_ViewDidLoad(IntPtr pobj, IntPtr sel, IntPtr* exception_gchandle)"

Any help would be much appreciated.

[vchelaru]

As a workaround I moved the behavior out of XAML and into C# and that seems tow solve it. No idea why:

    StatusBarBehavior StatusBar;

    public MyPage(...)
    {
        InitializeComponent();

        StatusBar = new StatusBarBehavior();
        StatusBar.StatusBarStyle = CommunityToolkit.Maui.Core.StatusBarStyle.LightContent;
        this.Behaviors.Add(StatusBar);
        ...