ef core 1.1 Autogenerated column using ValueGeneratedOnAdd - entity-framework

Question

Using EfCore 1.1, I am trying to have a autogenerated column using ValueGeneratedOnAdd. The problem is i am always getting value as "0". Do i have to manually do anything with the database table ?
Here is my model
public class Contact
{
public int Id { get; set; }
// This needs to be auto generated
public Int32 ContactIndex { get; set; }
public string FullName { get; set; }
public string Email { get; set; }
public DateTime LastAccessed { get; set; }
}
This is how my OnModelCreating looks like
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<Contact>()
.Property(c => c.ContactIndex)
.ValueGeneratedOnAdd();
// I tried following as well but it did't work
// .HasDefaultValueSql("IDENTITY(int, 1,1)");
;
}

Answer 1

ok I figured how to do it, but i really wanted to do that without using any annotations, and i still cannot figure out how to do it without annotations on model. So here is my solution.
You need to annotate your filed in the model like following
public class Contact
{
public int Id { get; set; }
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public Int32 ContactIndex { get; set; }
public string FullName { get; set; }
public string Email { get; set; }
public DateTime LastAccessed { get; set; }
}
and add OnModelCreating in your context class. This will tell entity framework to ignore the column while adding or updating records. Make sure you calling method .ValueGeneratedAddOrUpdate( ). If you use only .ValueGeneratedAdd( ) you will get errors while making updates.
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<Contact>()
.Property(c => c.ContactIndex)
.ValueGeneratedOnAddOrUpdate();
;
}
Generate and run your migrations and your migrations should include "SqlServerValueGenerationStrategy.IdentityColumn"
protected override void Up(MigrationBuilder migrationBuilder)
{
migrationBuilder.AddColumn<int>(
name: "ContactIndex",
table: "Contact",
nullable: false,
defaultValue: 0)
.Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn);
}