将对象转换为通用接口 [英] Casting an object to a generic interface

问题描述

我有以下界面:

internal interface IRelativeTo<T> where T : IObject
{
    T getRelativeTo();
    void setRelativeTo(T relativeTo);
}

和一堆(应该)实现它的类，例如:

and a bunch of classes that (should) implement it, such as:

public class AdminRateShift : IObject, IRelativeTo<AdminRateShift>
{
    AdminRateShift getRelativeTo();
    void setRelativeTo(AdminRateShift shift);
}

我意识到这三个不一样:

I realise that these three are not the same:

IRelativeTo<>
IRelativeTo<AdminRateShift>
IRelativeTo<IObject>

但尽管如此，我需要一种方法来处理所有不同的类，比如 AdminRateShift(和 FXRateShift、DetRateShift)，这些类都应该实现 IRelativeTo.假设我有一个将 AdminRateShift 作为对象返回的函数:

but nonetheless, I need a way to work with all the different classes like AdminRateShift (and FXRateShift, DetRateShift) that should all implement IRelativeTo. Let's say I have a function which returns AdminRateShift as an Object:

IRelativeTo<IObject> = getObjectThatImplementsRelativeTo(); // returns Object

通过针对接口编程，我可以做我需要做的事情，但我实际上无法将 Object 转换为 IRelativeTo 以便我可以使用它.

By programming against the interface, I can do what I need to, but I can't actually cast the Object to IRelativeTo so I can use it.

这是一个微不足道的例子，但我希望它能阐明我想要做什么.

It's a trivial example, but I hope it will clarify what I am trying to do.

推荐答案

如果我理解这个问题，那么最常见的方法是声明一个非通用的基接口，即

If I understand the question, then the most common approach would be to declare a non-generic base-interface, i.e.

internal interface IRelativeTo
{
    object getRelativeTo(); // or maybe something else non-generic
    void setRelativeTo(object relativeTo);
}
internal interface IRelativeTo<T> : IRelativeTo
    where T : IObject
{
    new T getRelativeTo();
    new void setRelativeTo(T relativeTo);
}

另一种选择是让您大量使用泛型进行编码......即您有像

Another option is for you to code largely in generics... i.e. you have methods like

void DoSomething<T>() where T : IObject
{
    IRelativeTo<IObject> foo = // etc
}

如果 IRelativeTo 是 DoSomething() 的参数，那么通常你不需要指定泛型类型自己论证 - 编译器会推断它 - 即

If the IRelativeTo<T> is an argument to DoSomething(), then usually you don't need to specify the generic type argument yourself - the compiler will infer it - i.e.

DoSomething(foo);

而不是

DoSomething<SomeType>(foo);

这两种方法都有好处.

这篇关于将对象转换为通用接口的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！