public partial class DataEntityContainer : ObjectContext
    {
        .......
        public ObjectSet<Car> Cars
        {
            get
            {
                if ((_Cars == null))
                {
                    _Cars = base.CreateObjectSet<Good>("Cars");
                }
                return _Cars;
            }
        }
        private ObjectSet<Car> _Cars;
   }

    [EdmEntityTypeAttribute(NamespaceName="DataEntity", Name="Car")]
    [Serializable()]
    [DataContractAttribute(IsReference=true)]
    public partial class Car : EntityObject
    {
        public static Car CreateCar(global::System.Guid id)
        {
            Car car = new Car();
            car.ID = id;
            return car;
        }

        [EdmScalarPropertyAttribute(EntityKeyProperty=true, IsNullable=false)]
        [DataMemberAttribute()]
        public global::System.Guid ID
        {
            get
            {
                return _ID;
            }
            set
            {
                if (_ID != value)
                {
                    OnIDChanging(value);
                    ReportPropertyChanging("ID");
                    _ID = StructuralObject.SetValidValue(value);
                    ReportPropertyChanged("ID");
                    OnIDChanged();
                }
            }
        }
        private global::System.Guid _ID;
        partial void OnIDChanging(global::System.Guid value);
        partial void OnIDChanged();
    
        ......
    }

    public partial class Car
    {
           public void DoSomething()
           {
              .........
           }
    }