Question

我想做的是:

class T : IEnumerable<string>, IEnumerable<int>
{
    string [] _strings = new string [20];
    int[] _ints = new int[20];

    public T() { }

    IEnumerator<string> IEnumerable<string>.GetEnumerator()
    {
        foreach (string str in _strings)
            yield return str;
    }

    IEnumerator<int> IEnumerable<int>.GetEnumerator()
    {
        foreach (int i in _ints)
            yield return i;
    }

    IEnumerator IEnumerable.GetEnumerator()
    {
        return this.GetEnumerator();
    }

}
//Using in code:
T t = new T();
foreach (int i in t)
   //to do something
foreach (string str in t)
   //to do stuff

我愿知道,有没有办法实现这一目标。是否有trick?

Answer 1

你们几乎都设法做到了落实<>> > 两个接口——你刚刚需要改变非遗传性执行,以显示你再次试图将哪些一般性执行交给他。例如:

IEnumerator IEnumerable.GetEnumerator()
{
    return ((IEnumerable<int>)this).GetEnumerator();
}

但是,由于你重新实施一个以上<代码>。 IE amountable<T> 接口你需要在每一座椅子中投放,显示使用:

T t = new T();
foreach (int i in (IEnumerable<int>) t)
   //to do something
foreach (string str in (IEnumerable<string>) t)

如果可能的话,我会强烈建议against这样做,这给阅读你的法典的人造成了许多混乱。

See section 8.8.4 of the C# Language specification for details of the composeder treatments the expression to iterate over in a foreach loop.

(用“热”接口执行one,由您提供某种“过失”——但我不认为会真正使之更好。)

Answer 2

我建议界定一些结构类型,其唯一领域是你类别的例子,最初是图形构造者,其唯一公共成员是GetE数字仪,并且采用E 数字和斜体;以你的基型号使用适当的方法。之后,您的原产阶级会执行一个成员,该成员会再次出现一个适当的障碍。

For example, if your class Foo had a GetStringEnumerator method which returned a type that implements IEnumerable<String>, you could have Foo.AsStrings return a struct FooStringEnumerable whose GetEnumerator method called Foo.GetStringEnumerator.

Note that by having your enumerable thing be a struct rather than a class, you would avoid having to create an extra object instance in the common case where it is used in a "for-each" loop, since both vb and c# would duck-type the GetEnumerator method instead of casting to IEnumerable or IEnumerable<T>.

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