Inheritance of generic type

Question

Let's assume we have following classess:

abstract class Vehicle {/**/}

class Truck : Vehicle {/**/}
class Bus : Vehicle {/**/}
//etc...

abstract class VehicleWheel<TVehicle> where TVehicle : Vehicle {/**/}

class TruckWheel : VehicleWheel<Truck> {/**/}
class BusWheel : VehicleWheel<Bus> {/**/}

Now, i want to create generic class "VehicleWheelCarrier", which is inherited from Vehicle, and has 1 parameter, which is any type of wheel:

abstract class VehicleWheelCarrier<TWheel> : Vehicle where TWheel:VehicleWheel

Unfortunatelly, this doesn't compile, as VehicleWheel requires parameter.

How to solve that?

Answer 1

You may add a non-generic base for wheel like this:

abstract class Vehicle {/**/}

class Truck : Vehicle {/**/}
class Bus : Vehicle {/**/}
//etc...

abstract class VehicleWheelBase { internal VehicleWheelBase() { } /*Non-generic definitions of Wheel*/}
abstract class VehicleWheel<TVehicle> : VehicleWheelBase where TVehicle : Vehicle {/**/}

class TruckWheel : VehicleWheel<Truck> {/**/}
class BusWheel : VehicleWheel<Bus> {/**/}

abstract class VehicleWheelCarrier<TWheel> : Vehicle where TWheel : VehicleWheelBase