在抽象类中使用泛型 [英] Using generics in abstract classes

问题描述

我工作的地方实现类需要实现T.名单的问题是，这不起作用抽象类：

I'm working on an abstract class where the implementing class needs to implement a list of T. The problem is that this doesn't work:

public class AbstractClass
{
    public int Id { get; set; }
    public int Name { get; set; }

    public abstract List<T> Items { get; set; }
}

public class Container : AbstractClass
{
    public List<Widgets> Items { get; set; }
}

我敢肯定，还有就是我缺少一个明显的答案，我知道我可以建立一个抽象基类将在列表中，但是当我用我的LINQ命令生成列表，抽象型（ItemBase）不与.ToList（）方法很好地发挥。就是我想要做如此独特？

I'm sure that there is an obvious answer that I'm missing, and I know that I can build an abstract base type to put in the list, but when I use my Linq command to build the list, the abstract type (ItemBase) doesn't play nicely with the .ToList() method. Is what I'm trying to do so unique?

推荐答案

您需要在类的声明为好，知道什么类型的 T 是：

You need the declaration on the class as well, to know what type T is:

public abstract class AbstractClass<T>
{
    public int Id { get; set; }
    public int Name { get; set; }

    public abstract List<T> Items { get; set; }
}

public class Container : AbstractClass<Widgets>
{
    public List<Widgets> Items { get; set; }
}

您也可以限制哪些T可以，好比说它必须实现的iWidget ：

You can also restrict what T can be, like say it must implement IWidgets:

public class AbstractClass<T> where T : IWidgets

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