由网友(深冬入心)分享简介：我有以下的类层次结构。 I have the following class hierarchy. class Header { IEnumerable Item { get; set; } .... }class HeaderA : Header { .... } // Item should ha...

我有以下的类层次结构。

I have the following class hierarchy.

class Header { IEnumerable<Item> Item { get; set; } .... }
class HeaderA : Header { .... } // Item should have the type of IEnumerable<ItemA>
class HeaderB : Header { .... } // Item should have the type of IEnumerable<ItemB>

class Item { .... }
class ItemA : Item { .... }
class ItemB : Item { .... }

是否有可能有编译时检查对项目的类型，以确保它的的IEnumerable＆LT;意达＆GT; ，的IEnumerable＆LT; ItemB＆GT; 为意达和 ItemB 分别是多少？有没有更好的设计？

Is it possible to have compile time checking on the type of Item to make sure it's IEnumerable<ItemA>, IEnumerable<ItemB> for ItemA and ItemB respectively? Is there any better design?

推荐答案

您可以更改标题类的定义，类型参数传递给它，那么你可以并处是：

You can change the definition of the Header class to pass the type parameter to it, then you could impose that:

    class Header<TItem> where TItem : Item { IEnumerable<TItem> Item { get; set; } }
    class HeaderA : Header<ItemA> { } // Item should have the type of IEnumerable<ItemA>
    class HeaderB : Header<ItemB> { } // Item should have the type of IEnumerable<ItemB>

    class Item { }
    class ItemA : Item { }
    class ItemB : Item { }