从基本接口集合创建派生接口的通用集合 [英] Create a generic collection of derived interfaces from a collection of base interfaces

问题描述

我有一个基本界面

public interface IBase
{
    ...
}

和从此基础派生的接口

public interface IChild : IBase
{
    ...
}

在我的代码中，我调用一个方法，该方法将向我返回一个 List< IBase> (旧版代码).使用此列表，我尝试填充 ObservableCollection< IChild> :

Within my code, I call a method which will return me a List<IBase> (legacy code). With this List I am trying to fill a ObservableCollection<IChild>:

List<IBase> baseList= GetListofBase();
ChildList = new ObservableCollection<IChild>();

// how to fill ChildList with the contents of baseList here?

我知道不可能从基本类型转换为派生接口，但是可以从基本接口创建派生实例吗?

I know it is not possible to cast from a base to a derived interface, but is it possible to create a derived instance from a base interface?

推荐答案

您不能用 List< IBase> 填充 ObservableCollection< IChild> .

由于继承理论的规定，您只能用 List< IChild> 填充 ObservableCollection< IBase> .

You can only fill an ObservableCollection<IBase> with List<IChild> because of inheritance theory rules.

由于IBase是IChild的简化版本，因此类型不匹配:您无法将IBase转换为IChild.

Since IBase is a reduced version of IChild, types can't match: you can't convert IBase to IChild.

由于IChild是IBase的扩展版本，因此类型可以匹配:您可以将IChild转换为IBase.

Since IChild is an extended version of IBase, types can match: you can convert IChild to IBase.

例如，丰田汽车是汽车，但所有汽车都不是丰田，因此您可以像对待汽车一样对丰田行事，但不能像对待丰田那样对汽车行事，因为丰田汽车具有一些抽象汽车所没有的东西和可能性.

For example a Toyota car is a Car but all cars are not a Toyota, so you can act on a Toyota as if it is a Car, but you can't act on a Car as if it is a Toyota because a Toyota car have some things and possibilities that abstract Car have not.

检查一下本教程，这个概念对于类和接口都是相同的:

Check this tutorial about that, this concept is the same for classes as interfaces:

什么是继承

关于继承的维基百科页面:

The wikipedia page about inheritance:

https://en.wikipedia.org/wiki/Inheritance_(对象-定向编程)

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