c# – EF7 beta6：保存多个实体时出错

无法跟踪“公司”,因为已经跟踪了具有相同密钥的此类型的另一个实例.对于新实体,请考虑使用IIdentityGenerator生成唯一键值.

这是我的代码：

public class MrBellhopContext : DbContext
{

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

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Company>(entity =>
        {
            entity.Key(c => c.CompanyId);

            entity.Index(c => c.Name);

            entity.Property(c => c.CompanyId).ValueGeneratedOnAdd();
        });

        modelBuilder.UseSqlServerIdentityColumns();

        base.OnModelCreating(modelBuilder);
    }

}


public class Company
{

    public int CompanyId { get; set; }

    public string Name { get; set; }

    public string Description { get; set; }

    public string Phone { get; set; }

    public string Email { get; set; }

    public short StatusId { get; set; }

}


public class CompanyRepository : ICompanyRepository
{

    MrBellhopContext _dbcontext;


    public async Task UpdateAsync(Company company)
    {
        _dbcontext.Update(company);
        await _dbcontext.SaveChangesAsync();
    }
}



[Route("api/[controller]")]
public class CompanyController : Controller
{


    [HttpPut]
    public async void UpdateAsync([FromBody] Company company)
    {
        if ((!ModelState.IsValid) || (company == null))
        {
            Context.Response.StatusCode = 400;
            return;
        }
        else
        {
            await _repository.UpdateAsync(company);
        }
    }

}

我试图通过删除ValueGeneratedOnAdd(),UseSqlServerIdentityColumns()或更改映射来解决它,但如果我尝试更新多个请求中的多个实体,我会得到异常：

>首先要求：更新CompanyId 8
>首先要求：更新CompanyId 9 !!错误

有谁知道如何解决这个问题？