我可以拥有可变数量的通用参数吗? [英] Can I have a variable number of generic parameters?

问题描述

在我的项目中，我有以下三个接口，它们由管理具有不同结构的各种业务对象的合并的类实现.

In my project I have the following three interfaces, which are implemented by classes that manage merging of a variety of business objects that have different structures.

public interface IMerger<TSource, TDestination>
{
    TDestination Merge(TSource source, TDestination destination);
}

public interface ITwoWayMerger<TSource1, TSource2, TDestination>
{
    TDestination Merge(TSource1 source1, TSource2 source2, TDestination destination);
}

public interface IThreeWayMerger<TSource1, TSource2, TSource3, TDestination>
{
    TDestination Merge(TSource1 source1, TSource2 source2, TSource3 source3, TDestination destination);
}

这很好用，但我宁愿有一个 IMerger 接口，它指定可变数量的 TSource 参数，类似这样(下面的示例使用 params; 我知道这不是有效的 C#):

This works well, but I would rather have one IMerger interface which specifies a variable number of TSource parameters, something like this (example below uses params; I know this is not valid C#):

public interface IMerger<params TSources, TDestination>
{
    TDestination Merge(params TSource sources, TDestination destination);
}

有什么方法可以实现这一点，或者功能上等效的东西吗?

It there any way to achieve this, or something functionally equivalent?

推荐答案

你不能.这是 API 的关键部分.但是，您可以在旁边做一些事情，例如接受 Type[] 参数.您可能还会想出一些奇特的流畅的 API/扩展方法"来做这件事，但老实说，这可能不值得；但类似于:

You can't. That is a key part of the API. You could, however, do something around the side, such as accepting a Type[] argument. You might also think up some exotic "fluent API / extension method" way of doing it, but to be honest it probably won't be worth it; but something like:

obj.Merge<FirstType>(firstData).Merge<SecondType>(secondData)
     .Merge<ThirdType>(thirdData).Execute<TDestination>(dest);

或使用泛型类型推断:

obj.Merge(firstData).Merge(secondData).Merge(thirdData).Execute(dest);

每个合并步骤都会简单地存储要做的工作，只能由 Execute 访问.

Each merge step would simple store away the work to do, only accessed by Execute.

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