没有找到适合实体类型 HierarchyId 的构造函数

我在 DotNet core 3.1 中工作，需要使用层次结构，我必须在表中使用 HierarchyId，并且我使用 Code First。但是当我尝试执行时添加迁移它返回此错误：

找不到实体类型“HierarchyId”的合适构造函数。以下构造函数的参数无法绑定到实体类型的属性：无法绑定“HierarchyId(SqlHierarchyId value)”中的“value”。

这是我的实体类

public class MyHClass
{
    public int Id { get; set; }
    [Required]
    public string Name { get; set; }
    public HierarchyId Level { get; set; }
}

这是我的上下文类，在添加 MyHClass 世界之前，它会正确查找表并将表添加到数据库中。

public class ArtiDbContext : IdentityDbContext<IdentityUser>
{
    public ArtiDbContext(DbContextOptions<MyDbContext> options)
        : base(options)
    {

    }

    public new DbSet<T> Set<T>() where T : BaseEntity
    {
        return base.Set<T>();
    }

    public DbSet<SampleEntity> SampleEntity { get; set; }
    public DbSet<MyHClass> MyHClasses { get; set; }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {

        base.OnModelCreating(modelBuilder);

    }
}

这是我安装的包：

<PackageReference Include="EntityFrameworkCore.SqlServer.HierarchyId" Version="1.0.0" />
<PackageReference Include="Microsoft.EntityFrameworkCore" Version="3.1.4" />
<PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="3.1.4" />
<PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="3.1.4">

有关更多信息，我也将整个错误放在这里：

PM> add-migration
cmdlet Add-Migration at command pipeline position 1
Supply values for the following parameters:
Name: gh
Build started...
Build succeeded.
System.InvalidOperationException: No suitable constructor found for entity type 'HierarchyId'. The following constructors had parameters that could not be bound to properties of the entity type: cannot bind 'value' in 'HierarchyId(SqlHierarchyId value)'.
   at Microsoft.EntityFrameworkCore.Metadata.Conventions.ConstructorBindingConvention.ProcessModelFinalized(IConventionModelBuilder modelBuilder, IConventionContext`1 context)
   at Microsoft.EntityFrameworkCore.Metadata.Conventions.Internal.ConventionDispatcher.ImmediateConventionScope.OnModelFinalized(IConventionModelBuilder modelBuilder)
   at Microsoft.EntityFrameworkCore.Metadata.Conventions.Internal.ConventionDispatcher.OnModelFinalized(IConventionModelBuilder modelBuilder)
   at Microsoft.EntityFrameworkCore.Metadata.Internal.Model.FinalizeModel()
   at Microsoft.EntityFrameworkCore.ModelBuilder.FinalizeModel()
   at Microsoft.EntityFrameworkCore.Infrastructure.ModelSource.CreateModel(DbContext context, IConventionSetBuilder conventionSetBuilder)
   at Microsoft.EntityFrameworkCore.Infrastructure.ModelSource.GetModel(DbContext context, IConventionSetBuilder conventionSetBuilder)
   at Microsoft.EntityFrameworkCore.Internal.DbContextServices.CreateModel()
   at Microsoft.EntityFrameworkCore.Internal.DbContextServices.get_Model()
   at Microsoft.EntityFrameworkCore.Infrastructure.EntityFrameworkServicesBuilder.<>c.<TryAddCoreServices>b__7_3(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 singletonCallSite, 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 singletonCallSite, 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.<>c__DisplayClass1_0.<RealizeService>b__0(ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngine.GetService(Type serviceType, 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_InternalServiceProvider()
   at Microsoft.EntityFrameworkCore.DbContext.Microsoft.EntityFrameworkCore.Infrastructure.IInfrastructure<System.IServiceProvider>.get_Instance()
   at Microsoft.EntityFrameworkCore.Infrastructure.Internal.InfrastructureExtensions.GetService[TService](IInfrastructure`1 accessor)
   at Microsoft.EntityFrameworkCore.Infrastructure.AccessorExtensions.GetService[TService](IInfrastructure`1 accessor)
   at Microsoft.EntityFrameworkCore.Design.Internal.DbContextOperations.CreateContext(Func`1 factory)
   at Microsoft.EntityFrameworkCore.Design.Internal.DbContextOperations.CreateContext(String contextType)
   at Microsoft.EntityFrameworkCore.Design.Internal.MigrationsOperations.AddMigration(String name, String outputDir, String contextType)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigrationImpl(String name, String outputDir, String contextType)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigration.<>c__DisplayClass0_0.<.ctor>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.<>c__DisplayClass3_0`1.<Execute>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)
No suitable constructor found for entity type 'HierarchyId'. The following constructors had parameters that could not be bound to properties of the entity type: cannot bind 'value' in 'HierarchyId(SqlHierarchyId value)'.

您需要添加x.UseHierarchyId()给你的Startup.cs

options.UseSqlServer(
    connectionString,
    x => x.UseHierarchyId());

BTW, SqlHierarchyId与 .NET Core 不兼容，除非您使用 dotMorten 的版本dotMorten.Microsoft.SqlServer.Types。 如果确实如此，那么您没有理由使用EntityFrameworkCore.SqlServer.HierarchyId at all.