.NET泛型中重载运算符约束的解决方案

没有直接的答案;运算符是静态的,不能用约束来表示-并且现有的primary不实现任何特定的接口(与可用于模拟大于/小于的IComparable[<t>]不同)。

但是,如果您只想让它工作,那么在.NET 3.5中有一些选项…

我建了一个图书馆 here 它允许高效、简单地访问具有泛型的运算符,例如:

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

它可以作为 MiscUtil

此外,在C 4.0中,通过 dynamic :

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

我也有一个.NET 2.0版本(一度),但测试较少。另一种选择是创建一个接口,例如

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

等等,但是你需要通过 ICalc<T>; 通过所有的方法,这会变得混乱。

我发现我可以很好地处理这个问题。前任。

ldarg.0
ldarg.1
add
ret

在泛型方法中编译,只要指定基元类型,代码就可以正常运行。可以扩展它来调用非基元类型上的运算符函数。

见 here .

有一段从互联网上偷来的代码,我用了很多。它使用 IL 基本算术运算符。这一切都是在一个 Operation<T> 泛型类,您所要做的就是将所需的操作分配给委托。喜欢 add = Operation<double>.Add .

使用方法如下:

public struct MyPoint
{
    public readonly double x, y;
    public MyPoint(double x, double y) { this.x=x; this.y=y; }
    // User types must have defined operators
    public static MyPoint operator+(MyPoint a, MyPoint b)
    {
        return new MyPoint(a.x+b.x, a.y+b.y);
    }
}
class Program
{
    // Sample generic method using Operation<T>
    public static T DoubleIt<T>(T a)
    {
        Func<T, T, T> add=Operation<T>.Add;
        return add(a, a);
    }

    // Example of using generic math
    static void Main(string[] args)
    {
        var x=DoubleIt(1);              //add integers, x=2
        var y=DoubleIt(Math.PI);        //add doubles, y=6.2831853071795862
        MyPoint P=new MyPoint(x, y);
        var Q=DoubleIt(P);              //add user types, Q=(4.0,12.566370614359172)

        var s=DoubleIt("ABC");          //concatenate strings, s="ABCABC"
    }
}

操作<t> 源代码由Paste Bin提供: http://pastebin.com/nuqdeY8z

属性如下:

/* Copyright (C) 2007  The Trustees of Indiana University
 *
 * Use, modification and distribution is subject to the Boost Software
 * License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
 * http://www.boost.org/LICENSE_1_0.txt)
 *  
 * Authors: Douglas Gregor
 *          Andrew Lumsdaine
 *          
 * Url:     http://www.osl.iu.edu/research/mpi.net/svn/
 *
 * This file provides the "Operations" class, which contains common
 * reduction operations such as addition and multiplication for any
 * type.
 *
 * This code was heavily influenced by Keith Farmer's
 *   Operator Overloading with Generics
 * at http://www.codeproject.com/csharp/genericoperators.asp
 *
 * All MPI related code removed by ja72. 
 */