c# - 工厂类不支持 SOLID 原则

Question

我的代码如下所示

 public interface ICar
{
    void Created();
}

public class BigCar : ICar
{
    public void Created()
    {

    }
}

public class SmallCar : ICar
{
    public void Created()
    {

    }
}


public class LuxaryCar : ICar
{
    public void Created()
    {

    }
}

public class CarFactory
{
    public ICar CreateCar(int carType)
    {
        switch (carType)
        {
            case 0:
                return new BigCar();
            case 1:
                return new SmallCar();
            case 2:
                return new LuxaryCar();
            default:
                break;
        }
        return null;
    }
}

在这段代码中，我有一个返回具体实例的工厂。但是每次我需要对 ICar 接口(interface)进行新的实现时，我都必须更改 CarFactory 的 CreateCar() 方法。看来我不支持 SOLID 原则的开闭原则。请建议是否有更好的方法来处理这种情况。

Answer 1

您可能希望使其可配置，如下所示:

void Main()
{
    // configurable array
    var factories = new ICarFactory[] { new BigCarFactory() };

    // create factory
    var realfactory = new CarFactory(factories);

    // create car
    var car = realfactory.CreateCar(0);
}

public class CarFactory : ICarFactory
{
    private ICarFactory[] _factories;

    public CarFactory (ICarFactory[] factories)
    {
        _factories = factories;

    }   
    public ICar CreateCar(int carType)
    {
        return _factories.Where(x=>x.SupportCar(carType)).First().CreateCar(carType);
    }

    public bool SupportCar(int type) => _factories.Any(x=>x.SupportCar(type));
}

public interface ICarFactory
{
    ICar CreateCar(int type);
    bool SupportCar(int type);
}

public class BigCarFactory : ICarFactory
{
    public ICar CreateCar(int carType)
    {
        if(carType != 0) throw new NotSupportedException();
        return new BigCar();
    }

    public bool SupportCar(int type) => type == 0;
}


public interface ICar
{
    void Created();
}

public class BigCar : ICar
{
    public void Created()
    {

    }
}

public class SmallCar : ICar
{
    public void Created()
    {

    }
}


public class LuxaryCar : ICar
{
    public void Created()
    {

    }
}