C＃中更复杂的扩展泛型

Question

我有两类具有泛型的树，我一无所知，我知道如何用<? extends ...>在Java中解决。

第一棵AI树：

abstract class AbstractAI<TCtrl> : MonoBehaviour where TCtrl: IRotableWeaponController

abstract class AbstractShipAI : AbstractAI<IShipController>

class ModularAI : AbstractShipAI

Some other classes that extend AbstractAI and use various modules

模块树：

abstract class AbstractModule<TAi, TCtrl> : AIModule where TAi: AbstractAI<TCtrl> where TCtrl: IRotableWeaponController
{
    public virtual void Init(TAi parent)
}

class ShootModule: AbstractModule<AbstractAI<IRotableWeaponController>, IRotableWeaponController>

Some other modules that extend AbstractModule and can be used only with some AIs, that have required capabilities

使用的控制器接口树：

interface IRotableWeaponController

interface IShipController: IRotableWeaponController

Other interfaces extending IRotableWeaponController...

问题是：

class ModularAI : AbstractShipAI
{
    public ShootModule shootModule;

    protected override void Start()
    {
        shootModule.Init(this); // Error: Argument type 'ModularAI' is not assignable to parameter type 'AbstractAI<IRotableWeaponController>'    
    }
}

[ModularAI是AbstractAI<IShipController>，IShipController是IRotableWeaponController，但出现错误。

在Java中，我会这样做：

abstract class AbstractModule<TAi, TCtrl> : AIModule where TAi: AbstractAI<? extends TCtrl> where TCtrl: IRotableWeaponController

我知道它有点复杂，可能有一种更好的方法来设计它（而且我可能最终有一天会付诸实践），但是我想知道如何解决这个问题。拜托，我该怎么做？

Answer 1

class Fruit { }
class Apple : Fruit { }
class FruitMaker<T> where T : Fruit { }

class Program
{
    static void HandleFruit(FruitMaker<Fruit> fruitMaker) { }

    static void Main()
    {
        FruitMaker<Apple> appelMaker = new FruitMaker<Apple>();
        FruitMaker<Fruit> fruitMaker = appelMaker; //cannot convert from 'FruitMaker<Apple>' to 'FruitMaker<Fruit>'
        HandleFruit(fruitMaker);

    }
}

您需要的是泛型协方差，您需要将FruitMaker<Apple>传递给期望FruitMaker<Fruit>的方法。这可以通过out关键字启用，您想要的是class FruitMaker<out T> where T : Fruit { }，但是您不能这样做，因为FruitMaker不是接口。您可以按以下方式解决此问题：

class Fruit { }
class Apple : Fruit { }
interface IFruitMaker<out T> where T : Fruit { }
class FruitMaker<T> : IFruitMaker<T> where T : Fruit { }

class Program
{
    static void HandleFruit(IFruitMaker<Fruit> fruitMaker) { }

    static void Main()
    {
        FruitMaker<Apple> appelMaker = new FruitMaker<Apple>();
        IFruitMaker<Fruit> fruitMaker = appelMaker; //this is allowed thanks to the out keyword
        HandleFruit(fruitMaker);

    }
}

注意，我引入一个界面只是为了添加out键盘。

Answer 2

interface IAbstractAI<out TCtrl> where TCtrl : IRotableWeaponController {
}

abstract class AbstractAI<TCtrl> : MonoBehaviour, IAbstractAI<TCtrl> where TCtrl : IRotableWeaponController {
}

abstract class AbstractModule<TAi, TCtrl> : AIModule where TAi : IAbstractAI<TCtrl> where TCtrl : IRotableWeaponController {
    public virtual void Init(TAi parent) {
    }
}

class ShootModule : AbstractModule<IAbstractAI<IRotableWeaponController>, IRotableWeaponController> {
}

class ModularAI : AbstractShipAI {
    public ShootModule shootModule;

    protected override void Start() {
        shootModule.Init(this); // Error: Argument type 'ModularAI' is not assignable to parameter type 'AbstractAI<IRotableWeaponController>'    
    }
}