类是否需要实现IEnumerable使用Foreach源 [英] Does Class need to implement IEnumerable to use Foreach

问题描述

这是在C＃中，我有我一些其他的DLL使用类。它没有实现IEnumerable，但有2种方法是传递回的IEnumerator。有没有一种方法，我可以使用这些foreach循环。我使用的是密封类。

This is in C#, I have a class that I am using from some else's DLL. It does not implement IEnumerable but has 2 methods that pass back a IEnumerator. Is there a way I can use a foreach loop on these. The class I am using is sealed.

推荐答案

的foreach 做的不的要求的IEnumerable ，出乎人们意料。它所需要的是一个方法的GetEnumerator 返回具有方法的MoveNext 和获取属性<$ C的任何对象$ C>当前与适当的签名

foreach does not require IEnumerable, contrary to popular belief. All it requires is a method GetEnumerator that returns any object that has the method MoveNext and the get-property Current with the appropriate signatures.

/编辑：在你的情况，但是，你的运气了。你可以平凡包装你的对象，但是，使其枚举：

/ In your case, however, you're out of luck. You can trivially wrap your object, however, to make it enumerable:

class EnumerableWrapper {
    private readonly TheObjectType obj;

    public EnumerableWrapper(TheObjectType obj) {
        this.obj = obj;
    }

    public IEnumerator<YourType> GetEnumerator() {
        return obj.TheMethodReturningTheIEnumerator();
    }
}

// Called like this:

foreach (var xyz in new EnumerableWrapper(yourObj))
    …;

/编辑：下面的方法，由几个人提出，确实的不的工作，如果该方法返回一个的IEnumerator ：

/ The following method, proposed by several people, does not work if the method returns an IEnumerator:

foreach (var yz in yourObj.MethodA())
    …;

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