EF7 beta5：嘗試插入子實體時出錯

我使用ASP.NET5和Entity Framework 7.0.0-beta 5創建了一個API。

我有如此處所述創建的Model，DbContext和Repository，當我嘗試使用子實體插入數據時，我的app會拋出異常：

“無法將值NULL插入列'Status'，表'Company';列不允許空值.INSERT失敗。”

Status屬性在我的公司實體中不為null，但我不知道為什麼EF無法插入子實體的值。 （在這種情況下，“1”）

這是堆棧跟踪：

   at Microsoft.Data.Entity.Relational.Update.ReaderModificationCommandBatch.Execute(RelationalTransaction transaction, IRelationalTypeMapper typeMapper, DbContext context, ILogger logger)
   at Microsoft.Data.Entity.Relational.Update.BatchExecutor.Execute(IEnumerable`1 commandBatches, IRelationalConnection connection)
   at Microsoft.Data.Entity.Relational.RelationalDataStore.SaveChanges(IReadOnlyList`1 entries)
   at Microsoft.Data.Entity.ChangeTracking.Internal.StateManager.SaveChanges(IReadOnlyList`1 entriesToSave)
   at Microsoft.Data.Entity.ChangeTracking.Internal.StateManager.SaveChanges(Boolean acceptAllChangesOnSuccess)
   at Microsoft.Data.Entity.DbContext.SaveChanges(Boolean acceptAllChangesOnSuccess)
   at Microsoft.Data.Entity.DbContext.SaveChanges()
   at **.Data.Repositories.CompanyRepository.Create(Company company) in D:\**.Data\Repositories\CompanyRepository.cs:line 36
   at **.API.Controllers.CompanyController.Create(Company company) in D:\**.API\Controllers\CompanyController.cs:line 48

這是代碼：

的DbContext

public class MrBellhopContext : DbContext
{

    public DbSet<Company> Company { get; set; }
    public DbSet<CompanyStatus> CompanyStatus { get; set; }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Company>().Table("Company");
        modelBuilder.Entity<Company>().Key(c => c.CompanyId);
        modelBuilder.Entity<Company>().Index(c => c.Name);
        modelBuilder.Entity<Company>().Reference(c => c.Status).InverseReference().ForeignKey<CompanyStatus>(cs => cs.StatusId);

        modelBuilder.Entity<CompanyStatus>().Table("CompanyStatus");
        modelBuilder.Entity<CompanyStatus>().Key(cs => cs.StatusId);

        base.OnModelCreating(modelBuilder);
    }

}

模型

public class Company
{

    public int CompanyId { get; set; }

    public string Name { get; set; }

    public string Email { get; set; }

    public CompanyStatus Status { get; set; }

    public DateTime CreatedAt { get; set; }

    public DateTime UpdatedAt { get; set; }

}

public class CompanyStatus
{

    public int StatusId { get; set; }

    public string Name { get; set; }

}

存儲庫 （僅創建方法）

    public int Create(Company company)
    {
        _dbcontext.Add(company);
        _dbcontext.SaveChanges();

        return company.CompanyId;
    }

有誰知道如何正確插入子實體？