Activate UseLazyLoadingProxies new error backing field #9688

cetin.sahin created one month ago

I tried to activate UseLazyLoadingProxies before and some entity collections are not virtual so in 9.2.3 version you updated these entities but when try it in latest version another error is thrown. I don't know if more errors will appear, because when you solve one error, it shows another. So I think you need to activate it in a project on your side and try it. So my new error says: InvalidOperationException: No backing field was found for property 'Tenant.ConnectionStrings'. Lazy-loaded navigations must have backing fields. Either name the backing field so that it is discovered by convention or configure the backing field to use. This occur probably ConnectionStrings defined as list but i am not sure. S i tried to exclude Tenant entity from LazyLoading but it did not work too.

Provide us with the following info: Template: app Created ABP Studio Version: 0.9.23 Current ABP Studio Version: 1.0.2 Tiered: Yes Multi-Tenancy: Yes UI Framework: blazor-server Theme: leptonx Theme Style: system Run Install Libs: Yes Database Provider: ef Database Management System: sqlserver Separate Tenant Schema: No Create Initial Migration: Yes Run Db Migrator: Yes Mobile Framework: none Public Website: No Include Tests: Yes Kubernetes Configuration: Yes Distributed Event Bus: none Use Local References: No Optional Modules: GDPR TextTemplateManagement LanguageManagement AuditLogging OpenIddictAdmin

Exception message and full stack trace: An unhandled exception occurred while processing the request. InvalidOperationException: No backing field was found for property 'Tenant.ConnectionStrings'. Lazy-loaded navigations must have backing fields. Either name the backing field so that it is discovered by convention or configure the backing field to use. Microsoft.EntityFrameworkCore.Infrastructure.ModelValidator.<ValidateFieldMapping>g__Validate|24_0(ITypeBase typeBase)

Stack Query Cookies Headers Routing InvalidOperationException: No backing field was found for property 'Tenant.ConnectionStrings'. Lazy-loaded navigations must have backing fields. Either name the backing field so that it is discovered by convention or configure the backing field to use. Microsoft.EntityFrameworkCore.Infrastructure.ModelValidator.<ValidateFieldMapping>g__Validate|24_0(ITypeBase typeBase) Microsoft.EntityFrameworkCore.Infrastructure.ModelValidator.ValidateFieldMapping(IModel model, IDiagnosticsLogger<Validation> logger) Microsoft.EntityFrameworkCore.Infrastructure.ModelValidator.Validate(IModel model, IDiagnosticsLogger<Validation> logger) Microsoft.EntityFrameworkCore.Infrastructure.RelationalModelValidator.Validate(IModel model, IDiagnosticsLogger<Validation> logger) Microsoft.EntityFrameworkCore.SqlServer.Infrastructure.Internal.SqlServerModelValidator.Validate(IModel model, IDiagnosticsLogger<Validation> logger) Microsoft.EntityFrameworkCore.Infrastructure.ModelRuntimeInitializer.Initialize(IModel model, bool designTime, IDiagnosticsLogger<Validation> validationLogger) Microsoft.EntityFrameworkCore.Infrastructure.ModelSource.CreateModel(DbContext context, ModelCreationDependencies modelCreationDependencies, bool designTime) Microsoft.EntityFrameworkCore.Infrastructure.ModelSource.GetModel(DbContext context, ModelCreationDependencies modelCreationDependencies, bool designTime) Microsoft.EntityFrameworkCore.Internal.DbContextServices.CreateModel(bool designTime) Microsoft.EntityFrameworkCore.Internal.DbContextServices.get_Model() Microsoft.EntityFrameworkCore.Infrastructure.EntityFrameworkServicesBuilder+<>c.<TryAddCoreServices>b__8_4(IServiceProvider p) Provide us with the following info: 🧐 Hint: If you are using the ABP Studio, you can see all the information about your solution from the configuration window, which opens when you right-click on the solution and click on the Solution Configuration button.

AI-Bot created one month ago

Support Team ABP Agent

To enable EF Core's lazy loading with UseLazyLoadingProxies, all navigation properties (including collections) must be marked as virtual and must have a discoverable backing field. The error you encountered:

InvalidOperationException: No backing field was found for property 'Tenant.ConnectionStrings'. Lazy-loaded navigations must have backing fields.

indicates that the ConnectionStrings property on the Tenant entity does not have a proper backing field, which is required for lazy loading proxies to work.

Solution

Backing Field Requirement:
EF Core's lazy loading requires that navigation properties (including collections) have a backing field. If the property is auto-implemented or does not follow EF Core's naming conventions for backing fields, you must explicitly define and configure the backing field.
How to Fix:
- Update the Tenant entity to define a private backing field for ConnectionStrings.
- Mark the navigation property as virtual.
- Configure the backing field in your OnModelCreating method using the Fluent API.

Example

public class Tenant : AggregateRoot<Guid>
{
    private List<TenantConnectionString> _connectionStrings = new List<TenantConnectionString>();

    public virtual ICollection<TenantConnectionString> ConnectionStrings
    {
        get => _connectionStrings;
        protected set => _connectionStrings = (List<TenantConnectionString>)value;
    }
}

And in your DbContext:

protected override void OnModelCreating(ModelBuilder builder)
{
    base.OnModelCreating(builder);

    builder.Entity<Tenant>()
        .HasMany(typeof(TenantConnectionString), "_connectionStrings")
        .WithOne()
        .HasForeignKey("TenantId");

    builder.Entity<Tenant>()
        .Navigation(e => e.ConnectionStrings)
        .UsePropertyAccessMode(PropertyAccessMode.Field);
}

This ensures EF Core can find and use the backing field for lazy loading.

If You Cannot Change the Entity:
If the Tenant entity comes from a NuGet package or ABP module and you cannot modify it directly, you will not be able to use lazy loading for that property. In this case, you must either:
- Avoid enabling lazy loading for the entire context, or
- Exclude the problematic entity from lazy loading and use explicit loading for its navigation properties.
General Recommendation:
Lazy loading is powerful but can introduce subtle bugs and performance issues. Consider using explicit loading (Include) or eager loading (WithDetailsAsync) for better control, especially in modular or layered ABP solutions.

References

ABP EF Core Integration & Lazy Loading

This response was generated by AI. If it didn’t solve your problem, feel free to post a new answer — our support team will jump in to help you soon.

cetin.sahin created one month ago

i tried even before AI says but it do not accept to exclude from builder. Also i cant change Tenant entity.it comes from dll

maliming created one month ago

Support Team Fullstack Developer

I will check this case. Thanks

maliming created one month ago

Support Team Fullstack Developer

By the way, why do you want to use lazy loading? What are the problems with explicit loading? Thanks.

cetin.sahin created one month ago

We're writing a web version of an existing desktop project, and DevExpress XpoObject is used there. Because XpoObject's lifecycle events aren't available in EFCore, we created that infrastructure. However, because the infrastructure we created involves very complex operations, we want to access the entity's collection we need at that moment via dbset.

maliming created one month ago

Support Team Fullstack Developer

It sounds like explicit loading could also solve your problem. Are you encountering any errors?

You can query entities and their navigation properties through the IRepository.

Thanks

cetin.sahin created one month ago

No it does not. because some case i need to get 5th 6th degree navigation property.

maliming created one month ago

Support Team Fullstack Developer

https://github.com/abpframework/abp/issues/

You can use Include and ThenInclude to load N degree navigation property. This is not a problem.

https://learn.microsoft.com/en-us/ef/core/querying/related-data/eager#including-multiple-levels

https://abp.io/docs/latest/framework/data/entity-framework-core#defaultwithdetailsfunc

cetin.sahin created one month ago

What you're referring to is Eager Loading. In the XpoObject lifecycle I mentioned earlier, many methods have countless references. With the approach you're suggesting, I would have to make sure that all places calling my method include the necessary navigation properties which isn't really manageable in my scenario

maliming created one month ago

Support Team Fullstack Developer

ok, I will update all modules to support this case.

Maybe 9.2.4 or 9.2.5

Thanks.

maliming created one month ago

Support Team Fullstack Developer

I can't reproduce the InvalidOperationException: No backing field was found for property 'Tenant.ConnectionStrings'. Lazy-loaded navigations must have backing fields. error in the latest 9.2.x.

Can you test your code in a new template project?

Thanks.

cetin.sahin created one month ago

I created a new project. when i try to add new entity i get same error again. i am sharing project with you but if you dont trust file you can create a new project . activate UseLazyLoadingProxies. generate entity from suite without update database and when start dbmigrator it shows error. By the way same error throws when starting the project too

Error Detail :

System.InvalidOperationException
  HResult=0x80131509
  Message=No backing field was found for property 'Tenant.ConnectionStrings'. Lazy-loaded navigations must have backing fields. Either name the backing field so that it is discovered by convention or configure the backing field to use.
  Source=Microsoft.EntityFrameworkCore
  StackTrace:
   at Microsoft.EntityFrameworkCore.Infrastructure.ModelValidator.<ValidateFieldMapping>g__Validate|24_0(ITypeBase typeBase)
   at Microsoft.EntityFrameworkCore.Infrastructure.ModelValidator.ValidateFieldMapping(IModel model, IDiagnosticsLogger`1 logger)
   at Microsoft.EntityFrameworkCore.Infrastructure.ModelValidator.Validate(IModel model, IDiagnosticsLogger`1 logger)
   at Microsoft.EntityFrameworkCore.Infrastructure.RelationalModelValidator.Validate(IModel model, IDiagnosticsLogger`1 logger)
   at Microsoft.EntityFrameworkCore.SqlServer.Infrastructure.Internal.SqlServerModelValidator.Validate(IModel model, IDiagnosticsLogger`1 logger)
   at Microsoft.EntityFrameworkCore.Infrastructure.ModelRuntimeInitializer.Initialize(IModel model, Boolean designTime, IDiagnosticsLogger`1 validationLogger)
   at Microsoft.EntityFrameworkCore.Infrastructure.ModelSource.CreateModel(DbContext context, ModelCreationDependencies modelCreationDependencies, Boolean designTime)
   at Microsoft.EntityFrameworkCore.Infrastructure.ModelSource.GetModel(DbContext context, ModelCreationDependencies modelCreationDependencies, Boolean designTime)
   at Microsoft.EntityFrameworkCore.Internal.DbContextServices.CreateModel(Boolean designTime)
   at Microsoft.EntityFrameworkCore.Internal.DbContextServices.get_Model()
   at Microsoft.EntityFrameworkCore.Infrastructure.EntityFrameworkServicesBuilder.&lt;&gt;c.&lt;TryAddCoreServices&gt;b__8_4(IServiceProvider p)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitFactory(FactoryCallSite factoryCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite callSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite callSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite callSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite callSite, ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.DynamicServiceProviderEngine.&lt;&gt;c__DisplayClass2_0.&lt;RealizeService&gt;b__0(ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService(ServiceIdentifier serviceIdentifier, ServiceProviderEngineScope serviceProviderEngineScope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
   at Volo.Abp.EntityFrameworkCore.AbpDbContextOptionsExtension.&lt;&gt;c__DisplayClass0_0.&lt;ApplyServices&gt;b__1(IServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitFactory(FactoryCallSite factoryCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite callSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite callSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite callSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite callSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite callSite, ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.DynamicServiceProviderEngine.&lt;&gt;c__DisplayClass2_0.&lt;RealizeService&gt;b__0(ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService(ServiceIdentifier serviceIdentifier, ServiceProviderEngineScope serviceProviderEngineScope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider)
   at Microsoft.EntityFrameworkCore.DbContext.get_DbContextDependencies()
   at Microsoft.EntityFrameworkCore.DbContext.get_ContextServices()
   at Microsoft.EntityFrameworkCore.DbContext.get_InternalServiceProvider()
   at Microsoft.EntityFrameworkCore.DbContext.Microsoft.EntityFrameworkCore.Infrastructure.IInfrastructure&lt;System.IServiceProvider&gt;.get_Instance()
   at Microsoft.EntityFrameworkCore.Infrastructure.DatabaseFacade.Microsoft.EntityFrameworkCore.Infrastructure.IInfrastructure&lt;System.IServiceProvider&gt;.get_Instance()
   at Microsoft.EntityFrameworkCore.RelationalDatabaseFacadeExtensions.GetRelationalService[TService](IInfrastructure`1 databaseFacade)
   at Microsoft.EntityFrameworkCore.RelationalDatabaseFacadeExtensions.MigrateAsync(DatabaseFacade databaseFacade, CancellationToken cancellationToken)
   at AbpSolution2.EntityFrameworkCore.EntityFrameworkCoreAbpSolution2DbSchemaMigrator.<MigrateAsync>d__2.MoveNext() in C:\Users\Yusuf\Documents\Projects\AbpSolution2\src\AbpSolution2.EntityFrameworkCore\EntityFrameworkCore\EntityFrameworkCoreAbpSolution2DbSchemaMigrator.cs:line 28
   at AbpSolution2.Data.AbpSolution2DbMigrationService.<MigrateDatabaseSchemaAsync>d__10.MoveNext() in C:\Users\Yusuf\Documents\Projects\AbpSolution2\src\AbpSolution2.Domain\Data\AbpSolution2DbMigrationService.cs:line 100
   at AbpSolution2.Data.AbpSolution2DbMigrationService.<MigrateAsync>d__9.MoveNext() in C:\Users\Yusuf\Documents\Projects\AbpSolution2\src\AbpSolution2.Domain\Data\AbpSolution2DbMigrationService.cs:line 53
   at AbpSolution2.DbMigrator.DbMigratorHostedService.<StartAsync>d__3.MoveNext() in C:\Users\Yusuf\Documents\Projects\AbpSolution2\src\AbpSolution2.DbMigrator\DbMigratorHostedService.cs:line 36
   at Microsoft.Extensions.Hosting.Internal.Host.<<StartAsync>b__14_1>d.MoveNext()
   at Microsoft.Extensions.Hosting.Internal.Host.<ForeachService>d__17`1.MoveNext()

maliming created one month ago

Support Team Fullstack Developer

Thanks. I will check your project.

cetin.sahin created one month ago

the url i shared is deleted from post. i am not sure you are deleted but if you do not get the url i can share again

maliming created one month ago

Support Team Fullstack Developer

Yes, I have downloaded it.

Thanks.

maliming created one month ago

Support Team Fullstack Developer

This is related to our DLL encryption. We will remove the encryption from the entity, which will solve the problem.

cetin.sahin created one month ago

In which version should we expect this update? Also can yo refund our ticket. Thanks.

maliming created one month ago

Support Team Fullstack Developer

9.2.4

Your ticket has been refunded.

Thanks.

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Activate UseLazyLoadingProxies new error backing field #9688

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