动态使用泛型是不可能的吗? [英] Is it impossible to use Generics dynamically?

问题描述

我需要在运行时创建一个使用泛型的类的实例，比如 class<T>，之前不知道它们将拥有的类型 T，我想做这样的事情:

I need to create at runtime instances of a class that uses generics, like class<T>, without knowing previously the type T they will have, I would like to do something like that:

public Dictionary<Type, object> GenerateLists(List<Type> types)
{
    Dictionary<Type, object> lists = new Dictionary<Type, object>();

    foreach (Type type in types)
    {
        lists.Add(type, new List<type>()); /* this new List<type>() doesn't work */
    }

    return lists;
}

...但我不能.我认为在通用括号内用 C# 编写类型变量是不可能的.还有其他方法吗?

...but I can't. I think it is not possible to write in C# inside the generic brackets a type variable. Is there another way to do it?

推荐答案

你不能那样做——泛型的要点主要是编译时类型安全——但你可以做到它带有反射:

You can't do it like that - the point of generics is mostly compile-time type-safety - but you can do it with reflection:

public Dictionary<Type, object> GenerateLists(List<Type> types)
{
    Dictionary<Type, object> lists = new Dictionary<Type, object>();

    foreach (Type type in types)
    {
        Type genericList = typeof(List<>).MakeGenericType(type);
        lists.Add(type, Activator.CreateInstance(genericList));
    }

    return lists;
}

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