实体框架异常：找不到适合实体类型“CultureInfo”的构造函数

Question

我有这个：

模型类

public class BusinessSelectList
{
    public int Id { get; set; }
    public string Name { get; set; }
    public bool IsBusinessGroup { get; set; }
    [NotMapped]
    public bool IsSelected { get; set; } = false;
}

数据库上下文

public class AppDbContext : DbContext
{
    public AppDbContext(DbContextOptions<AppDbContext> options) : base(options)
    {
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
    }

    public virtual DbQuery<BusinessSelectList> BusinessSelectList { get; set; 

    /** other virtual DbQuery properties **/
}

存储库

public class BusinessRepository :IBusinessRepository
{
    private readonly IHttpContextAccessor _httpAccessor;
    private readonly AppDbContext _context;

    public BusinessRepository(AppDbContext context, IHttpContextAccessor httpAccessor)
    {
        _context = context;
        _httpAccessor = httpAccessor;
    }

    public IEnumerable<BusinessSelectList> GetAsSelectList()
    {
        var query = @"exec webApp.usp_Business_GetAsSelectList @user";
        var p1 = new SqlParameter("user", _httpAccessor.HttpContext.User.Identity.Name);
        return _context.BusinessSelectList.FromSql(query, p1).ToList();
    }
}

错误

实体框架异常：找不到适合实体类型“CultureInfo”的构造函数

我试图寻找解决方案，但我没有找到任何解决方案。 这里有什么问题？ ：/

完整的例外是：

{System.InvalidOperationException: No suitable constructor found for entity type 'CultureInfo'. The following parameters could not be bound to properties of the entity: 'name', 'name', 'useUserOverride', 'cultureData', 'isReadOnly', 'culture', 'culture', 'useUserOverride', 'cultureName', 'textAndCompareCultureName'.
   at Microsoft.EntityFrameworkCore.Metadata.Conventions.Internal.ConstructorBindingConvention.Apply(InternalModelBuilder modelBuilder)
   at Microsoft.EntityFrameworkCore.Metadata.Conventions.Internal.ConventionDispatcher.ImmediateConventionScope.OnModelBuilt(InternalModelBuilder modelBuilder)
   at Microsoft.EntityFrameworkCore.Metadata.Conventions.Internal.ConventionDispatcher.OnModelBuilt(InternalModelBuilder modelBuilder)
   at Microsoft.EntityFrameworkCore.Metadata.Internal.Model.Validate()
   at Microsoft.EntityFrameworkCore.Infrastructure.ModelSource.CreateModel(DbContext context, IConventionSetBuilder conventionSetBuilder, IModelValidator validator)
   at Microsoft.EntityFrameworkCore.Infrastructure.ModelSource.<>c__DisplayClass5_0.<GetModel>b__1()
   at System.Lazy`1.ViaFactory(LazyThreadSafetyMode mode)
   at System.Lazy`1.ExecutionAndPublication(LazyHelper executionAndPublication, Boolean useDefaultConstructor)
   at System.Lazy`1.CreateValue()
   at Microsoft.EntityFrameworkCore.Infrastructure.ModelSource.GetModel(DbContext context, IConventionSetBuilder conventionSetBuilder, IModelValidator validator)
   at Microsoft.EntityFrameworkCore.Internal.DbContextServices.CreateModel()
   at Microsoft.EntityFrameworkCore.Internal.DbContextServices.get_Model()
   at Microsoft.EntityFrameworkCore.Infrastructure.EntityFrameworkServicesBuilder.<>c.<TryAddCoreServices>b__7_1(IServiceProvider p)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitFactory(FactoryCallSite factoryCallSite, ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(IServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(IServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(IServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(IServiceCallSite callSite, TArgument argument)
   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.get_DbContextDependencies()
   at Microsoft.EntityFrameworkCore.DbContext.get_Model()
   at Microsoft.EntityFrameworkCore.Internal.InternalDbQuery`1.get_EntityType()
   at Microsoft.EntityFrameworkCore.Internal.InternalDbQuery`1.get_EntityQueryable()
   at Microsoft.EntityFrameworkCore.Internal.InternalDbQuery`1.System.Linq.IQueryable.get_Provider()
   at Microsoft.EntityFrameworkCore.RelationalQueryableExtensions.FromSql[TEntity](IQueryable`1 source, RawSqlString sql, Object[] parameters)
   at MBPT.CoreWeb.Repository.BusinessRepository.GetAsSelectList() in C:\Users\czurbanlu\Source\Workspaces\Workspace\MBPT\MBPT.CoreWeb\MBPT.CoreWeb\Repository\BusinessRepository.cs:line 32}

Answer 1

在某个地方，您似乎在其中一个实体上拥有一个属性，例如：

public CultureInfo Foo { get; set; }

由于CultureInfo是一个类，因此实体框架会将其视为一个实体，甚至可能会为其创建一个数据库表，具体取决于实体的设置方式。 在任何一种情况下，当它尝试构建您的对象图时，它都会尝试填充此属性，但不能，因为CultureInfo没有无参数构造函数。

总而言之，找到您在何处完成此操作并将其删除。 如果您需要以某种方式保留文化信息，请保留一些您可以稍后用于获取适当CultureInfo实例的内容。 但是，您不能在实体本身上使用它。

Answer 2

我也有同样的问题。 就我而言，我有一个近乎空的数据访问层项目。 当我创建一个指向实体类型的导航链接时，问题来了又去，该实体类型在 DbContext 中作为 DbSet 不可用。

例如，下面的代码给出了与 OP 相同的问题：

    public class Organization
    {
        [Key]
        public Guid OrganizationId { get; set; }
        public string Name { get; set; }

        // Navigation properties
        public virtual ICollection<Pipeline> Pipelines { get; set; }
    }

    public class MyContext : DbContext
    {
        public MyContext()
        {
        }

        public MyContext(DbContextOptions<MyContext> dbContextOptions) : base(dbContextOptions)
        {

        }

        public DbSet<Organization> Organizations { get; set; }
}

虽然这段代码没有：

    public class Organization
    {
        [Key]
        public Guid OrganizationId { get; set; }
        public string Name { get; set; }

        // Navigation properties
 // COMMENTED OUT       public virtual ICollection<Pipeline> Pipelines { get; set; }
    }

    public class MyContext : DbContext
    {
        public MyContext()
        {
        }

        public MyContext(DbContextOptions<MyContext> dbContextOptions) : base(dbContextOptions)
        {

        }

        public DbSet<Organization> Organizations { get; set; }
}

问题可以通过两种方式解决：

• 出来评论导航链接
• 将属性DbSet<Pipeline>添加到 DbContext。

Answer 3

对于遇到此问题并且没有任何意见或解决方案解决您的问题的任何人，请确保您的表实体没有继承自 IDisposable 的某些内容（或可能只是不继承自 System.Data.DataTable）。

就我而言，我正在阅读的一些教程（公平地说，可能对我自己的好处来说太快了一点）继承了“System.Data.DataTable”。 我当时处于“非常快速地尝试 200 件事模式”并且忘记了我是用我的许多表实体之一继承它的。

您得到的错误非常不具体和模糊，所以希望这可以帮助那里的人！