C＃中的JavaScript扩展语法 [英] JavaScript spread syntax in C#

问题描述

在C＃中是否有任何实现，如 JavaScript的扩展语法？

Is there any implementation in C# like JavaScript's spread syntax?

var arr = new []{
   "1",
   "2"//...
};

Console.WriteLine(...arr);

推荐答案

没有差价选项。还有原因。

There isn't a spread option. And there are reasons.

1. 属性不是C＃中的数组，除非你使用params关键字


2. 使用param关键字的属性必须：
   
   

1. Properties aren't an array in C# unless you use the params keyword
2. Properties that use the param keyword would have to either:

1. 共享相同的类型


2. 拥有一个castable共享类型，例如double for numerics


3. 类型为object []（因为对象是所有内容的根类型）

然而，话说回来，你可以获得具有各种语言功能的类似功能。

However, having said that, you can get similar functionality with various language features.

回答你的例子：

C＃

var arr = new []{
   "1",
   "2"//...
};

Console.WriteLine(string.Join(", ", arr));

您提供的链接有以下示例：

The link you provide has this example:

Javascript Spread

function sum(x, y, z) {
  return x + y + z;
}

const numbers = [1, 2, 3];

console.log(sum(...numbers));
// expected output: 6

console.log(sum.apply(null, numbers));

参数
在C＃中，类型相同

Params In C#, with same type

public int Sum(params int[] values)
{
     return values.Sum(); // Using linq here shows part of why this doesn't make sense.
}

var numbers = new int[] {1,2,3};

Console.WriteLine(Sum(numbers));

在C＃中，使用不同的数字类型，使用double

In C#, with different numeric types, using double

public int Sum(params double[] values)
{
     return values.Sum(); // Using linq here shows part of why this doesn't make sense.
}

var numbers = new double[] {1.5, 2.0, 3.0}; // Double usually doesn't have precision issues with small whole numbers

Console.WriteLine(Sum(numbers));

反射
在C＃中，使用不同的数字类型，使用对象和反射，这可能是你最接近你要求的。

Reflection In C#, with different numeric types, using object and reflection, this is probably the closest to what you are asking for.

using System;
using System.Reflection;

namespace ReflectionExample
{
    class Program
    {
        static void Main(string[] args)
        {
            var paramSet = new object[] { 1, 2.0, 3L };
            var mi = typeof(Program).GetMethod("Sum", BindingFlags.Public | BindingFlags.Static);
            Console.WriteLine(mi.Invoke(null, paramSet));
        }

        public static int Sum(int x, double y, long z)
        {
            return x + (int)y + (int)z;
        }
    }
}

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