Problem creating foreign key in Entity

Question

I’m trying to create a Primary key composed, until everything well. With this I need to make a Foreign key composed.

I have more or less the following scenario (it is a hypothetical scenario but reflects what I need and my mistake):

public class Keys {
    [Key, Column(Order = 0)]
    public int Key_1 { get; set; }

    [Key, Column(Order = 1)]
    public int Key_2 { get; set; }

    // order is important here as defined in "KeyAuthorities" table
    [ForeignKey("KeyAuthorities", Column(Order = 0)]
    public int KeyAuthorities_Key_1 { get; set; }

    [ForeignKey("KeyAuthorities", Column(Order = 1)]
    public int KeyAuthorities_Key_2 { get; set; }

}

public class KeyAuthorities {
    [Key, Column(Order = 0)]
    public int KeyAuthorities_Key_1 { get; set; }

    [Key, Column(Order = 1)]
    public int KeyAuthorities_Key_2 { get; set; }

}

The Foreignkeyattribute on Property 'Keyauthorities' on type 'Portaladmcc.Models.Keys' is not Valid. The Foreign key name 'Keyauthorities' was not found on the dependent type 'Portaladmcc.Models.Keys'. The Name value should be a comma separated list of Foreign key Property Names.

What that mistake means?

Answer 1

The error indicates that the EF did not find the property with the name you defined as FK in the annotation.

You can try adding a navigation property to FK:

public class Keys {
    [Key, Column(Order = 0)]
    public int Key_1 { get; set; }

    [Key, Column(Order = 1)]
    public int Key_2 { get; set; }

    // order is important here as defined in "KeyAuthorities" table
    [ForeignKey("Authorities")]
    public int KeyAuthorities_Key_1 { get; set; }

    [ForeignKey("Authorities")]
    public int KeyAuthorities_Key_2 { get; set; }

    public KeyAuthorities Authorities { get; set; }
}

public class KeyAuthorities {
    [Key, Column(Order = 0)]
    public int KeyAuthorities_Key_1 { get; set; }

    [Key, Column(Order = 1)]
    public int KeyAuthorities_Key_2 { get; set; }

}

The other option to specify FK with annotations would be to annotate the navigation property with the names of the fields that form FK:

public class Keys {
    [Key, Column(Order = 0)]
    public int Key_1 { get; set; }

    [Key, Column(Order = 1)]
    public int Key_2 { get; set; }

    // order is important here as defined in "KeyAuthorities" table
    public int KeyAuthorities_Key_1 { get; set; }

    public int KeyAuthorities_Key_2 { get; set; }

    [ForeignKey("KeyAuthorities_Key_1, KeyAuthorities_Key_2")]
    public KeyAuthorities Authorities { get; set; }
}

public class KeyAuthorities {
    [Key, Column(Order = 0)]
    public int KeyAuthorities_Key_1 { get; set; }

    [Key, Column(Order = 1)]
    public int KeyAuthorities_Key_2 { get; set; }

}