Foreign key for different named columns Entity Framework

Question

public class Message
{
    [Key]
    public int MeesageId { get; set; }

    public int SenderId { get; set; }
    [ForeignKey("PersonId")]
    public virtual Person Sender { get; set; }

    public int ReceiverId { get; set; }
    [ForeignKey("PersonId")]
    public virtual Person Receiver { get; set; }

    public string Content { get; set; }
    public DateTime CreatedOn { get; set; }
    public bool Seen { get; set; }
}

public class Person
{
    public string Username { get; set; }
    [Key]
    public int PersonId { get; set; }
}

I'm getting this error:

The ForeignKeyAttribute on property 'Receiver' on type 'Finder.Models.Message' is not valid. The foreign key name 'PersonId' was not found on the dependent type 'Finder.Models.Message'. The Name value should be a comma-separated list of foreign key property names.

What I think I should do is rename ReceiverId to PersonId , so it matches the foreign key, but then the property names would be too messy. Any help would be appreciated

Answer 1

The ForeignKey attribute specifies which int property is the foreign key for the specified navigation property. So

public class Message
{
        [Key]
        public int MeesageId { get; set; }

        public int SenderId { get; set; }
        [ForeignKey("SenderId")]
        public virtual Person Sender { get; set; }

        public int ReceiverId { get; set; }
        [ForeignKey("ReceiverId")]
        public virtual Person Receiver { get; set; }

        public string Content { get; set; }
        public DateTime CreatedOn { get; set; }
        public bool Seen { get; set; }
}

Answer 2

It is better to use fluent api.

for example:

    public class Message
    {
      public int MeesageId { get; set; }
   
        public int SenderId { get; set; }
       
        public virtual Person Sender { get; set; }
   
        public int ReceiverId { get; set; }
       
        public virtual Person Receiver { get; set; }
   
        public string Content { get; set; }
   
        public DateTime CreatedOn { get; set; }
   
        public bool Seen { get; set; }
    }
   
    public class Person
    {
        public string Username { get; set; }
    
        public int PersonId { get; set; }
   
        public List<Message> SenderMessages { get; set; }
   
        public List<Message> RecieverMessages { get; set; }
    }
   
    public class MessageConfigurations : IEntityTypeConfiguration<Message>
    {
        public void Configure(EntityTypeBuilder<Message> builder)
        {
            builder.HasKey(x => x.MeesageId);
   
            builder.HasOne(x => x.Sender)
                .WithMany(x => x.SenderMessages)
                .HasForeignKey(x => x.SenderId)
                .OnDelete(DeleteBehavior.NoAction);
   
   
            builder.HasOne(x => x.Receiver)
                .WithMany(x => x.RecieverMessages)
                .HasForeignKey(x => x.ReceiverId)
                .OnDelete(DeleteBehavior.NoAction); 
        }
    }
   
   
    public class PersonConfigurations : IEntityTypeConfiguration<Person>
    {
        public void Configure(EntityTypeBuilder<Person> builder)
        {
            builder.HasKey(x => x.PersonId);
   
        }
    }