Question

ASP .NET 4 MVC，Entity Framework 4.4的问题上面相对缺乏经验，如果问题很明显就很抱歉，但是我难倒了，谷歌foo不起作用。

首先使用代码创建数据库（使用Devart MySQL dot net connector）获得例外

* System.InvalidOperationException：外键组件“Clinician_ClientId”不是“Clinician_Client”类型的声明属性。验证它是否未从模型中明确排除，并且它是有效的原始属性。

在我尝试使用有效负载实现连接表之前，事情进展顺利。目的：客户可以有很多临床医生，临床医生可以有很多客户，有效负载是开始/结束时期。

下面的代码只是为了要点

  /// <summary>
/// Represents a clinician of the system
/// </summary>
public class Clinician
{
    [Key]
    [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
    public int clinicianId { get; set; }


    [ForeignKey("UserDetails")]
    public int UserDetailsId { get; set; }
    public virtual UserDetails UserDetails { get; set; }

    [ForeignKey("Clinician_Client")]
    public int Clinician_ClientId { get; set; }
    public virtual ICollection<Clinician_Client> Clinician_Client { get; set; }
}

客户端类

/// <summary>
/// Represents a client of the system
/// </summary>
public class Client
{
    [Key]
    [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
    public int clientId { get; set; }

    //Snip other fields

    [ForeignKey("UserDetails")]
    public int UserDetailsId { get; set; }
    public virtual UserDetails UserDetails { get; set; }

    [ForeignKey("Clinician_Client")]
    public int Clinician_ClientId { get; set; }
    public virtual ICollection<Clinician_Client> Clinician_Client { get; set; }


}

加入表

/// <summary>
/// Represents a clinicians care period over a client
/// </summary>
public class Clinician_Client
{
    [Key]
    [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
    public int Clinician_ClientId { get; set; }

    public DateTime start_dttm { get; set; }
    public DateTime end_dttm { get; set; }

    //foreign keys
//    [ForeignKey("Client")]
    public int ClientId { get; set; }
//    public virtual Client Client { get; set; }

//    [ForeignKey("Clinician")]
    public int ClinicianId { get; set; }
//    public virtual Clinician Clinician { get; set; }
}

上下文

  public class UsersContext : DbContext
{
    public UsersContext()
        : base("DefaultConnection")
    {
    }

    public DbSet<UserProfile> UserProfiles { get; set; }
    public DbSet<UserDetails> UserDetails { get; set; }
    public DbSet<Client> Client { get; set; }
    public DbSet<Clinician> Clinician { get; set; }
    public DbSet<Clinician_Client> Clinician_Client { get; set; }
}

尝试过使用nullable（连接是可选的），连接表上的外键，无济于事。问题是我不理解错误，该字段是类和模型的一部分。

Answer 1

这是你的问题： -

[ForeignKey("Clinician_Client")]
public int Clinician_ClientId { get; set; }
public virtual ICollection<Clinician_Client> Clinician_Client { get; set; }

您认为Clinician_ClientId的价值应该是什么？

它不能是相关Clinician_ClientId对象的Clinician_Client，因为您希望每个Clinician（以及每个Client）与 <相关联em>很多 Clinician_Client对象。

看起来模型构建器正在查看类型ICollection<Clinician_Client>以查找与Clinician_ClientId匹配的属性（例如“Id”）。它没有，因为它是ICollection<Clinician_Client>，而不是Clinician_Client。

另外，您可能需要考虑为Clinician_Client对象提供更好的名称来描述其有效负载。也许是“CarePeriod”？

尝试更多类似的内容： -

public class Clinician
{
  public int ClinicianId { get; set; }

  public virtual ICollection<CarePeriod> CarePeriods { get; set; }

  ...
}

public class Client
{
  public int ClientId { get; set; }

  public virtual ICollection<CarePeriod> CarePeriods { get; set }

  ...
}

public class CarePeriod
{
  public int CarePeriodId { get; set; }

  public int ClinicianId { get; set; }
  public virtual Clinician Clinician { get; set; }

  public int ClientId { get; set; }
  public virtual Client Client { get; set; }

  ...
}

你不应该需要使用[Key]属性等等。默认约定应该包括你，除非我遗漏了你的连接器。

Code First Joining Table，“表未声明属性的键”

1 个答案: