c# - 嵌套在静态类中的类中的扩展方法

Question

我知道我们不能在嵌套类中使用扩展方法，并且该选择背后的原因非常有道理，我不是来谈论这种情况的。

是否有设计原因导致无法在嵌套在 static class 中的类中使用扩展方法？

public static class MyClass1
{
    public static class MyClass2
    {
        public static int Add(this int a, int b) //Doesn't compile
        {
            return a + b;
        }
    }
}

是否仅仅因为它是一个需要更多工作的“极端情况”并且被认为是无用的？还是这背后有其他设计原因？

Answer 1

在此answer , Eric Lippert 认为

Unless the feature is justified by some real-world user need, we're not going to take on the considerable costs of designing, implementing, testing, documenting and maintaining the feature.

他接着说

We considered it carefully for a long time and decided that on the basis of that consideration, the costs of doing the feature (extension methods in nested, generic static class) were not justified by the benefits accrued.

但是，您可以提交功能请求 here .