EF单向一对多关系

Question

I have an IdentityUser class which has a navigation property called Logins which is of type Collection .

public class IdentityUser : IUser
{
    public IdentityUser();
    public IdentityUser(string userName);

    public virtual ICollection<IdentityUserClaim> Claims { get; }
    public virtual string Id { get; set; }
    public virtual ICollection<IdentityUserLogin> Logins { get; }
    public virtual string PasswordHash { get; set; }
    public virtual ICollection<IdentityUserRole> Roles { get; }
    public virtual string SecurityStamp { get; set; }
    public virtual string UserName { get; set; }
}

In the IdentityUserLogin class there is a navigation property called User which is of type IdentityUser .

public class IdentityUserLogin
{
    public IdentityUserLogin();

    public virtual string LoginProvider { get; set; }
    public virtual string ProviderKey { get; set; }
    public virtual IdentityUser User { get; set; }
    public virtual string UserId { get; set; }
}

From this I can see that

1. the IdentityUser can have 0 to many IdentityUserLogin .
2. IdentityUserLogin must have a IdentityUser .

I tried:

        this.HasRequired(t => t.User)
            .WithRequiredPrincipal();

but it was looking for a foreign key of IdentityUser_Id but it should be using UserId (which is a property of IdentityUserLogin

so then I tried:

        this.HasRequired(t => t.User)
            .WithMany(t => t.Logins)
            .HasForeignKey(t => t.UserId);

but I get an error stating:

IdentityUserLogin_User_Source: : Multiplicity is not valid in Role 'IdentityUserLogin_User_Source' in relationship 'IdentityUserLogin_User'. Because the Dependent Role refers to the key properties, the upper bound of the multiplicity of the Dependent Role must be '1'.

Does anyone know how I can declare the relationship and specify the Foreign Key?

Update 1

This is my IdentityUserLogin map class:

public class IdentityUserLoginMap : EntityTypeConfiguration<IdentityUserLogin>
{
    public IdentityUserLoginMap()
    {
        // Primary Key
        this.HasKey(t => t.UserId);

        // Properties
        this.Property(t => t.LoginProvider)
            .IsRequired()
            .HasMaxLength(128);

        this.Property(t => t.ProviderKey)
            .IsRequired()
            .HasMaxLength(128);

        this.Property(t => t.UserId)
            .IsRequired()
            .HasMaxLength(128);

        // Table & Column Mappings
        this.ToTable("IdentityUserLogins");
        this.Property(t => t.LoginProvider).HasColumnName("LoginProvider");
        this.Property(t => t.ProviderKey).HasColumnName("ProviderKey");
        this.Property(t => t.UserId).HasColumnName("UserId");

        // Relationships
        this.HasRequired(t => t.User)
            .WithRequiredPrincipal();
    }
}

As you can see, I am setting a primary key

Update 2

Just to give a bit more of an explanation, here is the users table:

CREATE TABLE [dbo].[IdentityUsers](
    [Id] [nvarchar](128) NOT NULL,
    [UserName] [nvarchar](max) NULL,
    [PasswordHash] [nvarchar](max) NULL,
    [SecurityStamp] [nvarchar](max) NULL,
    [Discriminator] [nvarchar](128) NOT NULL,
 CONSTRAINT [PK_dbo.IdentityUsers] PRIMARY KEY CLUSTERED 
(
    [Id] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
)

and the IdentityUserLogin table should look like this:

CREATE TABLE [dbo].[IdentityUserLogins](
    [LoginProvider] [nvarchar](128) NOT NULL,
    [ProviderKey] [nvarchar](128) NOT NULL,
    [UserId] [nvarchar](128) NOT NULL,
PRIMARY KEY CLUSTERED 
(
    [UserId] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

but when I run my code on a new database I get this:

CREATE TABLE [dbo].[IdentityUserLogins](
    [UserId] [nvarchar](128) NOT NULL,
    [LoginProvider] [nvarchar](128) NOT NULL,
    [ProviderKey] [nvarchar](128) NOT NULL,
    [IdentityUser_Id] [nvarchar](128) NULL,
 CONSTRAINT [PK_dbo.IdentityUserLogins] PRIMARY KEY CLUSTERED 
(
    [UserId] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

as you can see, the IdentityUser_Id is obsolete, it should be using the primary key. That is my objective :)

Answer 1

You might be confusing EF by not providing a Primary key property to your class IdentityUserLogin . I think in this case EF is taking UserId as your primary key. Since primary key cannot be duplicate, and the relationship you are mapping says WithMany they conflict with each other.

Update 1

This is conflicting with your model:

this.HasRequired(t => t.User).WithRequiredPrincipal();

because on class IdentityUser you have

public virtual ICollection&ltIdentityUserLogin> Logins { get; set; }

You need to use WithMany(t => t.Logins) in order to match your configuration with the model.

Update 2
This is a One-One relationship you need

public class IdentityUser
{
  ... 
  public virtual IdentityUserLogin Login { get; set; }
  ...
}

and

this.HasRequired(t => t.User).WithRequiredPrincipal(t => t.Login);