Custom IDataListSource error: "ValueFactory attempted to access the Value property of this instance."

[hfloyd]

I am working on a custom IDataListSource , but after compiling, the site fails to load with the error:

InvalidOperationException: ValueFactory attempted to access the Value property of this instance.

System.Lazy<T>.ViaFactory(LazyThreadSafetyMode mode)
System.Lazy<T>.ExecutionAndPublication(LazyHelper executionAndPublication, bool useDefaultConstructor)
System.Lazy<T>.CreateValue()
System.Lazy<T>.get_Value()
Umbraco.Cms.Web.Common.UmbracoContext.UmbracoContext.get_PublishedSnapshot()
Umbraco.Cms.Infrastructure.DependencyInjection.UmbracoBuilderExtensions+<>c.<AddCoreInitialServices>b__0_11(IServiceProvider factory)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor<TArgument, TResult>.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitRootCache(ServiceCallSite callSite, RuntimeResolverContext context)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite callSite, RuntimeResolverContext context)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor<TArgument, TResult>.VisitCallSite(ServiceCallSite callSite, TArgument argument)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor<TArgument, TResult>.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitRootCache(ServiceCallSite callSite, RuntimeResolverContext context)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite callSite, RuntimeResolverContext context)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor<TArgument, TResult>.VisitCallSite(ServiceCallSite callSite, TArgument argument)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor<TArgument, TResult>.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitRootCache(ServiceCallSite callSite, RuntimeResolverContext context)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor<TArgument, TResult>.VisitCallSite(ServiceCallSite callSite, TArgument argument)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite callSite, ServiceProviderEngineScope scope)
Microsoft.Extensions.DependencyInjection.ServiceProvider.CreateServiceAccessor(Type serviceType)
System.Collections.Concurrent.ConcurrentDictionary<TKey, TValue>.GetOrAdd(TKey key, Func<TKey, TValue> valueFactory)
Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService(Type serviceType, ServiceProviderEngineScope serviceProviderEngineScope)
Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type serviceType)
Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
Umbraco.Cms.Core.Composing.CollectionBuilderBase<TBuilder, TCollection, TItem>.CreateItem(IServiceProvider factory, Type itemType)
Umbraco.Cms.Core.Composing.CollectionBuilderBase<TBuilder, TCollection, TItem>+<>c__DisplayClass12_0.<CreateItems>b__0(Type x)
System.Linq.Enumerable+SelectArrayIterator<TSource, TResult>.ToArray()
System.Linq.Enumerable.ToArray<TSource>(IEnumerable<TSource> source)
Umbraco.Cms.Core.Composing.CollectionBuilderBase<TBuilder, TCollection, TItem>.CreateItems(IServiceProvider factory)
Umbraco.Cms.Core.Composing.CollectionBuilderBase<TBuilder, TCollection, TItem>+<>c__DisplayClass16_0.<CreateItemsFactory>b__0()
System.Lazy<T>.ViaFactory(LazyThreadSafetyMode mode)
System.Lazy<T>.ExecutionAndPublication(LazyHelper executionAndPublication, bool useDefaultConstructor)
System.Lazy<T>.CreateValue()
System.Lazy<T>.get_Value()
Umbraco.Cms.Core.Composing.LazyReadOnlyCollection<T>.EnsureCollection()
Umbraco.Community.Contentment.Composing.ContentmentListItemCollection..ctor(Func<IEnumerable<IContentmentListItem>> items)
System.RuntimeMethodHandle.InvokeMethod(object target, ref Span<object> arguments, Signature sig, bool constructor, bool wrapExceptions)
System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, object[] parameters, CultureInfo culture)
Microsoft.Extensions.DependencyInjection.ActivatorUtilities+ConstructorMatcher.CreateInstance(IServiceProvider provider)
Microsoft.Extensions.DependencyInjection.ActivatorUtilities.CreateInstance(IServiceProvider provider, Type instanceType, object[] parameters)
Umbraco.Extensions.ServiceProviderExtensions.CreateInstance(IServiceProvider serviceProvider, Type type, object[] args)
Umbraco.Extensions.ServiceProviderExtensions.CreateInstance<T>(IServiceProvider serviceProvider, object[] args)
Umbraco.Cms.Core.Composing.CollectionBuilderBase<TBuilder, TCollection, TItem>.CreateCollection(IServiceProvider factory)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor<TArgument, TResult>.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitRootCache(ServiceCallSite callSite, RuntimeResolverContext context)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor<TArgument, TResult>.VisitCallSite(ServiceCallSite callSite, TArgument argument)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor<TArgument, TResult>.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitRootCache(ServiceCallSite callSite, RuntimeResolverContext context)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor<TArgument, TResult>.VisitCallSite(ServiceCallSite callSite, TArgument argument)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor<TArgument, TResult>.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitRootCache(ServiceCallSite callSite, RuntimeResolverContext context)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor<TArgument, TResult>.VisitCallSite(ServiceCallSite callSite, TArgument argument)
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite callSite, ServiceProviderEngineScope scope)
Microsoft.Extensions.DependencyInjection.ServiceProvider.CreateServiceAccessor(Type serviceType)
System.Collections.Concurrent.ConcurrentDictionary<TKey, TValue>.GetOrAdd(TKey key, Func<TKey, TValue> valueFactory)
Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService(Type serviceType, ServiceProviderEngineScope serviceProviderEngineScope)
Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type serviceType)
Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
Umbraco.Cms.Core.Composing.CollectionBuilderBase<TBuilder, TCollection, TItem>.CreateItem(IServiceProvider factory, Type itemType)
Umbraco.Cms.Core.Composing.CollectionBuilderBase<TBuilder, TCollection, TItem>+<>c__DisplayClass12_0.<CreateItems>b__0(Type x)
System.Linq.Enumerable+SelectArrayIterator<TSource, TResult>.ToArray()
System.Linq.Enumerable.ToArray<TSource>(IEnumerable<TSource> source)
Umbraco.Cms.Core.Composing.CollectionBuilderBase<TBuilder, TCollection, TItem>.CreateItems(IServiceProvider factory)
Umbraco.Cms.Core.Composing.CollectionBuilderBase<TBuilder, TCollection, TItem>+<>c__DisplayClass16_0.<CreateItemsFactory>b__0()
System.Lazy<T>.ViaFactory(LazyThreadSafetyMode mode)
System.Lazy<T>.ExecutionAndPublication(LazyHelper executionAndPublication, bool useDefaultConstructor)
System.Lazy<T>.CreateValue()
System.Lazy<T>.get_Value()
Umbraco.Cms.Core.Composing.LazyReadOnlyCollection<T>.EnsureCollection()
Umbraco.Cms.Core.Composing.LazyReadOnlyCollection<T>.get_Value()
Umbraco.Cms.Core.Composing.LazyReadOnlyCollection<T>.GetEnumerator()
Umbraco.Cms.Core.Composing.BuilderCollectionBase<TItem>.GetEnumerator()
System.Linq.Enumerable+WhereEnumerableIterator<TSource>.MoveNext()
System.Collections.Generic.HashSet<T>.UnionWith(IEnumerable<T> other)
System.Linq.Enumerable+UnionIterator<TSource>.FillSet()
System.Linq.Enumerable+UnionIterator<TSource>.GetCount(bool onlyIfCheap)
System.Linq.Enumerable.Count<TSource>(IEnumerable<TSource> source)
Umbraco.Cms.Core.Composing.LazyReadOnlyCollection<T>.EnsureCollection()
Umbraco.Cms.Core.Composing.LazyReadOnlyCollection<T>.get_Value()
Umbraco.Cms.Core.Composing.LazyReadOnlyCollection<T>.GetEnumerator()
Umbraco.Cms.Core.Composing.BuilderCollectionBase<TItem>.GetEnumerator()
System.Linq.Enumerable.TryGetFirst<TSource>(IEnumerable<TSource> source, Func<TSource, bool> predicate, out bool found)
System.Linq.Enumerable.FirstOrDefault<TSource>(IEnumerable<TSource> source, Func<TSource, bool> predicate)
Umbraco.Cms.Core.PropertyEditors.PropertyEditorCollection.TryGet(string alias, out IDataEditor editor)
Umbraco.Cms.Infrastructure.Persistence.Factories.DataTypeFactory.BuildEntity(DataTypeDto dto, PropertyEditorCollection editors, ILogger<IDataType> logger, IConfigurationEditorJsonSerializer serializer)
Umbraco.Cms.Infrastructure.Persistence.Repositories.Implement.DataTypeRepository.<PerformGetAll>b__12_1(DataTypeDto x)
System.Linq.Enumerable+SelectListIterator<TSource, TResult>.ToArray()
System.Linq.Enumerable.ToArray<TSource>(IEnumerable<TSource> source)
Umbraco.Cms.Infrastructure.Persistence.Repositories.Implement.DataTypeRepository.PerformGetAll(int[] ids)
Umbraco.Cms.Core.Cache.DefaultRepositoryCachePolicy<TEntity, TId>.GetAll(TId[] ids, Func<TId[], IEnumerable<TEntity>> performGetAll)
Umbraco.Cms.Core.Services.Implement.DataTypeService.GetAll(int[] ids)
Umbraco.Cms.Core.Models.PublishedContent.PublishedContentTypeFactory.GetDataType(int id)
Umbraco.Cms.Core.Models.PublishedContent.PublishedPropertyType..ctor(string propertyTypeAlias, int dataTypeId, bool isUserProperty, ContentVariation variations, PropertyValueConverterCollection propertyValueConverters, IPublishedModelFactory publishedModelFactory, IPublishedContentTypeFactory factory)
Umbraco.Cms.Core.Models.PublishedContent.PublishedPropertyType..ctor(IPublishedContentType contentType, IPropertyType propertyType, PropertyValueConverterCollection propertyValueConverters, IPublishedModelFactory publishedModelFactory, IPublishedContentTypeFactory factory)
Umbraco.Cms.Core.Models.PublishedContent.PublishedContentTypeFactory.CreatePropertyType(IPublishedContentType contentType, IPropertyType propertyType)
Umbraco.Cms.Core.Models.PublishedContent.PublishedContentType+<>c__DisplayClass2_0.<.ctor>b__0(IPropertyType x)
System.Linq.Enumerable+SelectEnumerableIterator<TSource, TResult>.ToList()
System.Linq.Enumerable.ToList<TSource>(IEnumerable<TSource> source)
Umbraco.Cms.Core.Models.PublishedContent.PublishedContentType..ctor(IContentTypeComposition contentType, IPublishedContentTypeFactory factory)
Umbraco.Cms.Core.Models.PublishedContent.PublishedContentTypeFactory.CreateContentType(IContentTypeComposition contentType)
Umbraco.Cms.Infrastructure.PublishedCache.PublishedSnapshotService.<LoadContentFromLocalDbLocked>b__60_0(IContentType x)
System.Linq.Enumerable+SelectArrayIterator<TSource, TResult>.MoveNext()
Umbraco.Cms.Infrastructure.PublishedCache.ContentStore.SetAllContentTypesLocked(IEnumerable<IPublishedContentType> types)
Umbraco.Cms.Infrastructure.PublishedCache.PublishedSnapshotService.LoadContentFromLocalDbLocked(bool onStartup)
Umbraco.Cms.Infrastructure.PublishedCache.PublishedSnapshotService.<EnsureCaches>b__52_1()
Umbraco.Cms.Infrastructure.PublishedCache.PublishedSnapshotService.LockAndLoadContent(Func<bool> action)
Umbraco.Cms.Infrastructure.PublishedCache.PublishedSnapshotService.<EnsureCaches>b__52_0()
System.Threading.LazyInitializer.EnsureInitializedCore<T>(ref T target, ref bool initialized, ref object syncLock, Func<T> valueFactory)
System.Threading.LazyInitializer.EnsureInitialized<T>(ref T target, ref bool initialized, ref object syncLock, Func<T> valueFactory)
Umbraco.Cms.Infrastructure.PublishedCache.PublishedSnapshotService.EnsureCaches()
Umbraco.Cms.Infrastructure.PublishedCache.PublishedSnapshotService.CreatePublishedSnapshot(string previewToken)
Umbraco.Cms.Web.Common.UmbracoContext.UmbracoContext+<>c__DisplayClass11_0.<.ctor>b__0()
System.Lazy<T>.ViaFactory(LazyThreadSafetyMode mode)
System.Lazy<T>.ExecutionAndPublication(LazyHelper executionAndPublication, bool useDefaultConstructor)
System.Lazy<T>.CreateValue()
System.Lazy<T>.get_Value()
Umbraco.Cms.Web.Common.UmbracoContext.UmbracoContext.get_PublishedSnapshot()
Umbraco.Cms.Web.Common.UmbracoContext.UmbracoContext.get_Content()
Umbraco.Cms.Web.Website.Routing.UmbracoRouteValueTransformer.TransformAsync(HttpContext httpContext, RouteValueDictionary values)
System.Threading.Tasks.ValueTask<TResult>.get_Result()
System.Runtime.CompilerServices.ValueTaskAwaiter<TResult>.GetResult()
Microsoft.AspNetCore.Mvc.Routing.DynamicControllerEndpointMatcherPolicy.ApplyAsync(HttpContext httpContext, CandidateSet candidates)
Microsoft.AspNetCore.Routing.Matching.DfaMatcher.SelectEndpointWithPoliciesAsync(HttpContext httpContext, IEndpointSelectorPolicy[] policies, CandidateSet candidateSet)
Microsoft.AspNetCore.Routing.EndpointRoutingMiddleware.<Invoke>g__AwaitMatcher|8_0(EndpointRoutingMiddleware middleware, HttpContext httpContext, Task<Matcher> matcherTask)
SixLabors.ImageSharp.Web.Middleware.ImageSharpMiddleware.Invoke(HttpContext httpContext, bool retry)
StackExchange.Profiling.MiniProfilerMiddleware.Invoke(HttpContext context) in MiniProfilerMiddleware.cs
Umbraco.Cms.Web.Common.Middleware.UmbracoRequestMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
Umbraco.Cms.Web.Common.Middleware.UmbracoRequestMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
Microsoft.AspNetCore.Builder.UseMiddlewareExtensions+<>c__DisplayClass6_1+<<UseMiddlewareInterface>b__1>d.MoveNext()
Umbraco.Cms.Web.Common.Middleware.PreviewAuthenticationMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
Microsoft.AspNetCore.Builder.UseMiddlewareExtensions+<>c__DisplayClass6_1+<<UseMiddlewareInterface>b__1>d.MoveNext()
Umbraco.Cms.Web.Common.Middleware.UmbracoRequestLoggingMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
Microsoft.AspNetCore.Builder.UseMiddlewareExtensions+<>c__DisplayClass6_1+<<UseMiddlewareInterface>b__1>d.MoveNext()
SeoToolkit.Umbraco.RobotsTxt.Core.Middleware.RobotsTxtMiddleware.Invoke(HttpContext context)
Umbraco.Forms.Web.HttpModules.ProtectFormUploadRequestsMiddleware.InvokeAsync(HttpContext context, RequestDelegate next)
Microsoft.AspNetCore.Builder.UseMiddlewareExtensions+<>c__DisplayClass6_1+<<UseMiddlewareInterface>b__1>d.MoveNext()
UmbracoProject.Startup+<>c+<<Configure>b__4_0>d.MoveNext() in Startup.cs
+
				await next();
Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

The issue seems to be with Dependency Injection - I was injecting a custom Service into the IDataListSource. If I remove that service from the CTOR, the error doesn't occur.

The custom service is initiated in the "Startup.cs", and works in other contexts, so I am trying to pinpoint why it is blowing up here.
I have tried declaring it as services.AddSingleton<MyService>(); and as services.AddScoped<MyService>(); but neither works.

Has anyone else come across this sort of issue and have any insights?

[leekelleher]

@hfloyd Sometimes dependency injection feels like dark magic.

I'm not sure if this helps or not, but here's how I had to do it on the UmbracoTagsDataListSource code...

https://github.com/leekelleher/umbraco-contentment/blob/4.4.1/src/Umbraco.Community.Contentment/DataEditors/DataList/DataSources/UmbracoTagsDataListSource.cs#L74-L76

By injecting the IHttpContextAccessor and requesting the required service at the point I need to use it.

var tagQuery = _httpContextAccessor.HttpContext.RequestServices.GetRequiredService<ITagQuery>();