实体框架代码首先使用Fluent API映射外键 [英] Entity Framework Code First Mapping Foreign Key Using Fluent API

问题描述

我有一个用户可以有几个地址的情况。因此，我在我的用户类上有一个ICollection。但是我也希望用户能够选择一个默认的地址。所以我做了以下工作：

  public class User 
 {
 public int Id {get;组; } 
 public int？ DefaultAddressId {get;组; } 
 [ForeignKey（DefaultAddressId）] 
 public virtual Address DefaultAddress {get;组; } 
 public virtual ICollection< Address>地址{get;组; $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ 
 
 $ p $想删除 public virtual Address DefaultAddress {get;组; } 总之，保持DefaultAddressId并使用Fluent API进行映射，因为当前设置会导致很多麻烦（在这个和其他类中，我有类似的设置）。那么可以使用流畅的api来实现吗？
 
 
 
 更新： 
地址类目前没有任何引用用户类，这是一个单向的关系。但是，一个地址只属于一个用户，这不是很多关系。这是地址类：
  public class Address 
 {
 public int Id {get;组; } 
 public string Name {get;组; } 
 public string Details {get;组; } 
 public virtual Area Area {get;组; } 
} 
  
 
 
解决方案
我会亲自移动外键关系从用户到地址，并添加一个 IsDefaultAddress  property on the address class。
  public class Address 
 {
 public int Id {get;组; } 
 
 //此属性标记FK关系
 public virtual User User {get;组; } 
 
 public string Name {get;组; } 
 public string Details {get;组; } 
 public virtual Area Area {get;组; } 
 
 //此属性指示这是否是用户的默认地址
 public bool IsDefaultAddress {get;组; } 
} 
  
 EF将知道需要一个外键 地址和用户之间的关系。
 
 
 
这将简化您的模型很多。也就是说，如果一个地址只能属于一个用户（如Slauma在评论中提出的）。
 
I have the situation where a User can have several addresses. Accordingly, I have an ICollection on my user class. But I also want the user to be able to choose a default address. So I've done the following:
public class User 
{
    public int Id { get; set; }
    public int? DefaultAddressId { get; set; }
    [ForeignKey("DefaultAddressId")]
    public virtual Address DefaultAddress { get; set; }
    public virtual ICollection<Address> Addresses { get; set; }
    //properties were removed for purpose of this post
}
I would like to remove the public virtual Address DefaultAddress { get; set; } altogether, keep the DefaultAddressId and map it using the Fluent API instead because the current setup is causing a lot of trouble (in this and other classes where I have a similar setup). So can this be done using the fluent api?

UPDATE:
The address class currently doesn't have any reference to the User class, it's a uni-directional relationship. But yes, an address belongs to only ONE user, it's not a many to many relationship. Here's the address class:
public class Address
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Details { get; set; }
    public virtual Area Area { get; set; }
}

解决方案
I would personally move the Foreign Key relation from User to Address, and add an IsDefaultAddress property on the address class.
public class Address
{
    public int Id { get; set; }

    // This property marks the FK relation
    public virtual User User { get; set; }

    public string Name { get; set; }
    public string Details { get; set; }
    public virtual Area Area { get; set; }

    // This property signals whether this is the user's default address
    public bool IsDefaultAddress { get; set; }
}
EF will know that it needs a Foreign Key relation between Address and User.

This would simplify your model a great deal. That is, of course, if an address can only belong to one user (as asked by Slauma in the comments).

                        
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