CSharp冷知识-IEnumerator

类实现 IEnumerator 接口可以实现foreach循环

只要提供IEnumerator GetEnumerator便可实现foreach循环

IEnumerator

var mc = new MyClass(5);
foreach(var item in mc)
{

}

class MyClass : IEnumerator
{
    int length;
    public MyClass(int length)
    {
        this.length = length;
    }
    public IEnumerator GetEnumerator()
    {
        for (int i = 0; i < length; i++)
        {
            yield return i.ToString();
        }
    }
}
//
var mc = new MyClass(5);
foreach(var item in mc)
{

}

class MyClass
{
    int length;
    public MyClass(int length)
    {
        this.length = length;
    }
    public IEnumerator GetEnumerator()
    {
        for (int i = 0; i < length; i++)
        {
            yield return i.ToString();
        }
    }
}
//
foreach(var item in 5)
{

}
public class MyExtensions
{
    public static IEnumerator GetEnumerator(this int count)
    {
        for (int i = 0; i < count; i++)
        {
            yield return i.ToString();
        }
    }
}