c# - EF7 beta5 : Error trying to insert child entity

Question

我使用 ASP.NET5 和 Entity Framework 7.0.0-beta 5 创建了一个 API。

我按照描述创建了模型、DbContext 和存储库 here ，当我尝试使用子实体插入数据时，我的应用程序抛出异常:

“无法将 NULL 值插入表‘公司’的‘状态’列；该列不允许空值。插入失败。”

我的 Company 实体中的 Status 属性不为空，但我不知道为什么 EF 无法插入子实体的值。 (在本例中为“1”)

这是堆栈跟踪:

   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

代码如下:

数据库上下文

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);
    }

}

型号

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; }

}

Repository(仅创建方法)

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

        return company.CompanyId;
    }

有谁知道如何正确插入子实体？

Answer 1

尝试将 Repository 方法更改为:

public int Create(Company company)
{
    using (MyDbcontextdbcontext context = new MyDbcontext()) 
    { 
        context.Entry(company).State = EntityState.Added; 
        context.SaveChanges(); 
    }
}

更多信息:https://msdn.microsoft.com/en-us/data/jj592676.aspx