具有void输入的Lambda表达式

Question

好的,非常愚蠢的问题.

x => x * 2

是一个lambda,代表与委托相同的东西

int Foo(x) { return x * 2; }

但是什么是lambda相当于

int Bar() { return 2; }

??

非常感谢!

Answer 1

相当于nullary lambda () => 2.

Answer 2

那将是:

() => 2

用法示例:

var list = new List<int>(Enumerable.Range(0, 10));
Func<int> x = () => 2;
list.ForEach(i => Console.WriteLine(x() * i));

根据评论中的要求,以下是上述样本的细分......

// initialize a list of integers. Enumerable.Range returns 0-9,
// which is passed to the overloaded List constructor that accepts
// an IEnumerable<T>
var list = new List<int>(Enumerable.Range(0, 10));

// initialize an expression lambda that returns 2
Func<int> x = () => 2;

// using the List.ForEach method, iterate over the integers to write something
// to the console.
// Execute the expression lambda by calling x() (which returns 2)
// and multiply the result by the current integer
list.ForEach(i => Console.WriteLine(x() * i));

// Result: 0,2,4,6,8,10,12,14,16,18

Answer 3

如果没有参数,可以使用().

() => 2;