.NET泛型中重载运算符约束的解决方案 [英] Solution for overloaded operator constraint in .NET generics

问题描述

如果我想要一个泛型方法只接受重载运算符的类型，例如减法运算符，我该怎么办.我尝试使用接口作为约束，但接口不能有运算符重载.

What would I do if I want to have a generic method that only accepts types that have overloaded an operator, for instance the subtraction operator. I tried using an interface as a constraint but interfaces can't have operator overloading.

实现这一目标的最佳方法是什么?

What is the best way to achieve this?

推荐答案

没有立即答复；操作符是静态的，不能用约束来表达 - 现有的原语没有实现任何特定的接口(与 IComparable[<T>] 相反，它可用于模拟大于/小于).

There is no immediate answer; operators are static, and cannot be expressed in constraints - and the existing primatives don't implement any specific interface (contrast to IComparable[<T>] which can be used to emulate greater-than / less-than).

然而；如果你只是想让它工作，那么在 .NET 3.5 中有一些选项......

However; if you just want it to work, then in .NET 3.5 there are some options...

我在这里整理了一个库以及使用泛型简单访问运算符 - 例如:

I have put together a library here that allows efficient and simple access to operators with generics - such as:

T result = Operator.Add(first, second); // implicit <T>; here

它可以作为 MiscUtil

此外，在 C# 4.0 中，这可以通过 dynamic 实现:

Additionally, in C# 4.0, this becomes possible via dynamic:

static T Add<T>(T x, T y) {
    dynamic dx = x, dy = y;
    return dx + dy;
}

我也有(曾经)一个 .NET 2.0 版本，但测试较少.另一种选择是创建一个接口，例如

I also had (at one point) a .NET 2.0 version, but that is less tested. The other option is to create an interface such as

interface ICalc<T>
{
    T Add(T,T)() 
    T Subtract(T,T)()
} 

等，但随后您需要通过所有方法传递 ICalc;，这会变得混乱.

etc, but then you need to pass an ICalc<T>; through all the methods, which gets messy.

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