Csharp 如何实现具有定义的返回类型的通用接口

如果您需要具有成员的泛型版本的非泛型，那么您确实需要两个接口.这是需要阴影方法的情况之一.

试试这些:

public interface IGeometry
{
    IGeometry Translate(in v2 vector);
    IGeometry MoveTo(in v2 vector);
}

public interface IGeometry<T> : IGeometry where T : IGeometry<T>
{
    new T Translate(in v2 vector);
    new T MoveTo(in v2 vector);
}

现在可以隐式实现泛型接口，显式实现非泛型接口.

public readonly struct Circle : IGeometry<Circle>
{
    private readonly v2 _o;
    private readonly double _r, _area, _circum;
    public v2 Origin => _o;
    public double Radius => _r;
    public double Circumference => _circum;

    public Circle(in v2 origin, in double radius)
    {
        _o = origin;
        _r = radius;
        _area = _r * _r * Math.PI;
        _circum = _r * 2 * Math.PI;
    }

    public Circle Translate(in v2 translation) => new(_o + translation, _r);
    public Circle MoveTo(in v2 position) => new(position, _r);

    IGeometry IGeometry.Translate(in v2 vector) => this.Translate(vector);
    IGeometry IGeometry.MoveTo(in v2 vector) => this.MoveTo(vector);
}

现在，您可以执行以下操作:

Circle circle1 = new Circle();
Circle circle2 = circle1.Translate(new v2());
IGeometry geometry1 = circle1;
IGeometry geometry2 = geometry1.Translate(new v2());
Circle circle2a = (Circle)geometry2;

对非泛型接口方法的调用调用泛型版本以保持类型安全.

但是，请记住，您可以合法地实施以下操作:

public readonly struct Square : IGeometry<Circle>

你需要小心不要这样做.