Entity First Composite Key

C#

public class Raffle
{
    public int RaffleId { get; set; }
    public virtual List<Ticket> Tickets { get; set; }
}

public class Ticket
{
    [Key, Column(Order = 0)]
    [DatabaseGenerated(DatabaseGeneratedOption.None)]
    public int TicketNumber { get; set; }
    [Key, ForeignKey("Raffle"), Column(Order = 1)]
    public int RaffleId { get; set; }
    public virtual Raffle Raffle { get; set; }
}