EF Core 5 - 在自定义连接表中设置自定义属性值

Question

Based on examples, I created the following custom join table (using EF Core 5), since I needed an extra property in my custom join table:

modelBuilder.Entity<Property>(property =>
{
    property
        .HasMany(_ => _.Addresses)
        .WithMany(_ => _.Properties)
        .UsingEntity<PropertyAddress>(
            _ => _.HasOne(_ => _.Address).WithMany().HasForeignKey(_ => _.AddressId),
            _ => _.HasOne(_ => _.Property).WithMany().HasForeignKey(_ => _.PropertyId));
});

public class PropertyAddress
{
    public string PropertyId { get; set; }
    public string AddressId { get; set; }
    public int SequenceNumber { get; set; }
    public Property Property { get; set; }
    public Address Address { get; set; }
}

public class Property
{
    public ICollection<Address> Addresses { get; set; }
}

public class Address
{
    public ICollection<Property> Properties { get; set; }
}

The custom join table PropertyAddress is working as expected, however: How can I (programmatically) set the values for the custom property PropertyAddress.SequenceNumber before saving/updating records? (Because the whole joining mechanism is (now) still being handled 'behind the scene' by EF Core.)

Answer 1

1-First, you should have public DbSet PropertyAddress{ get; set; } in your DBContext ,then use it to insert your object. example:

1-Entity

public class GroupMember
{
    public int GroupMemberId { get; set; }

    [Required]
    public int UserId { get; set; }
    [Required]
    public int GroupId { get; set; }
    [Required]
    public DateTime JoinDate { get; set; }
    [Required]
    public int RoleTypeGroupId { get; set; }

    //Navigation
    public User User { get; set; }
    public Group Group { get; set; }
    public RoleTypeGroup RoleType { get; set; }
}

2-DbContext

public class AppDataContext : DbContext
{
  //Code

    public DbSet<GroupMember> GroupMembers { get; set; }

}

3-you need create object of PropertyAddress and set his value as you want.

4- use EF to insert the object or update it

 unitOfWork.GroupMemberRepository.Add(groupMember);
  unitOfWork.SaveChanges();