EF组合主键HasKey

namespace EFModel
{
    using ……;

    public partial class AppDbContext : DbContext
    {
        public AppDbContext() : base("name=EFModels") { }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            modelBuilder.Entity()
              .HasKey(t => new { t.MachineId, t.MachineOperationEnumItemId, t.OperateDatetime });
        }
    }
}