Entity Framework: Autoincrement ID with second Key part

Question

I have a code first EF model class like this:

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

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

Is it possible to auto increment Id if it is 0?

For example: I want to add a dataset like

Id = 1, Language = "En"

It works fine. Then, I want to add the following:

Id = 1, Language = "De"

It works fine too. But yet, I want to add this one:

Id = 0, Language = "En"

Id is 0, so the DB should generate an Id for me:

Id = 2, Language = "En"

---

Is there no way, I know I can generate an Id my self. But what happen if two threads try to add an element with the same Id? Can I prevent this?

Answer 1

Class

    [Table("Test")]
    class Test
    {
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        [Key, Column(Order = 0)]
        public int Id { get; set; }

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

    }

Insert Rec

using (var db = new TestDbContext())
{
      db.Test.Add(new Test { Id = 0, Language = "En" });
      db.Test.Add(new Test { Id = 0, Language = "Sb" });

      db.SaveChanges();    
 }

Result

Id Language
1 En
2 Sb
3 En
4 Sb

Rrerence: Entity Framework: how to generate an auto-increment ID field