动作迭代器

Question

我将如何创建委托“动作”的迭代器。我可以将序列输入 foreach 循环并在继续下一个操作之前完成每个操作。

是否也可以在委托“动作”中支持多个收益？

    public void SequenceTest()
    {
        List<Func<IEnumerator>> sequence = new List<Func<IEnumerator>> { () => Do(1), () => Do(2), () => Do(3) };

        Play (sequence);
    }

    private IEnumerator Play (IList<Func<IEnumerator>> sequence)
    {
        foreach (Func<IEnumerator> act in sequence)
        {
            yield return act();
        }
    }

    private IEnumerator Do(int num)
    {
        Console.WriteLine ("Starting " + num);

        Console.WriteLine ("step A");
        for(int i=0; i < 100; i++)
        {
            Console.WriteLine(".");
        }

        Console.WriteLine ("Ending " + num);

        yield return null;
    }

    private IEnumerator DoMulti(int num)
    {
        Console.WriteLine ("Starting " + num);

        Console.WriteLine ("step A");
        for(int i=0; i < 100; i++)
        {
            Console.WriteLine("v");
        }
        yield return null;


        Console.WriteLine ("step B");
        for(int i=0; i < 100; i++)
        {
            Console.WriteLine(".");
        }

        Console.WriteLine ("Ending " + num);

        yield break;
    }

Answer 1

你想要做的事情可以通过一个简单的扩展方法来实现……

void Main()
{
    IEnumerable<int> numbers = new List<int> { 1, 2, 3, 4, 5, 6, 7, 8 };
    numbers.Each(Console.WriteLine);
}

public static class Extensions 
{
    public static IEnumerable<T> Each<T>(this IEnumerable<T> enumerable, Action<T> action)
    {
        foreach (var element in enumerable)
        {
            action.Invoke(element);
        }

        return enumerable;
    }
}