c# - Entity Framework 关键问题

Question

当我尝试登录时出现以下错误:

Project.Model.Identity.UserLogin: : EntityType 'UserLogin' has no key defined. Define the key for this EntityType. UserLogins: EntityType: EntitySet 'UserLogins' is based on type 'UserLogin' that has no keys defined.

我正在尝试在我的 dbcontext 中使用复合键

  // Primary Key
  this.HasKey(t => new { t.LoginProvider, t.ProviderKey, t.UserId });

但它似乎无法拾取它，看起来它正在模型中而不是上下文中搜索键，因为当我在模型中添加“[Key]”关键字时它提示必须将 HasKey 用于复合键

public partial class UserLogin
{
    [Key]
    public string LoginProvider { get; set; }
    [Key]
    public string ProviderKey { get; set; }
    [Key]
    public string UserId { get; set; }
    public virtual User User { get; set; }
}

我该如何克服这个问题？我是否要在模型中添加 HasKey？如果是，如何添加以及为什么它没有在上下文中提取它？

Answer 1

如文档中所述，

When you have composite keys, Entity Framework requires you to define an order of the key properties. You can do this using the Column annotation to specify an order.

尝试修改代码如下:

public partial class UserLogin
{
    [Key]
    [Column(Order=1)]
    public string LoginProvider {get; set;}
    [Key]
    [Column(Order=2)]
    public string ProviderKey {get; set; }
    // and so on...
}