我如何知道在运行时扩展我的基类的类？ [英] How can I know the classes that extend my base class at runtime?

问题描述

在 运行时 期间，我想使用扩展我的基类的类填充一个下拉列表。目前我有一个枚举，这是我用来填充该列表，但是我想添加额外的类（而其他人正在添加类），并且不希望为此目的维护一个枚举。我想添加一个新的类和魔术（反思可能）该类出现在列表中，没有添加代码为下拉列表写入，或添加任何其他枚举。

During runtime, I would like to populate a drop down list with classes that have extended my base class. Currently I have an enum, and this is what I use to populate that list, but I want to add additional classes (and other people are adding classes) and do not want to have to maintain an enum for this purpose. I would like to add a new class and magically (reflection possibly) that class appears in the list without any addition code written for the drop down, or any additional enum added.

class Animal { ... }

enum AllAnimals { Cat, Dog, Pig };
class Cat : Animal {...}
class Dog : Animal {...}
class Pig : Animal {...}

有没有办法完成这个？

推荐答案

使用反射来获取加载的程序集，然后通过作为基类子类的所有类型枚举。

Use reflection to get the loaded assemblies and then enumerate through all types that are a subclass of your base class.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            var assemblies = AppDomain.CurrentDomain.GetAssemblies();
            var types = new List<Type>();

            foreach (var assembly in assemblies)
                types.AddRange(assembly.GetTypes().Where(x => x.IsSubclassOf(typeof(Animal))));

            foreach (var item in types)
                Console.WriteLine(item.Name);
        }
    }

    class Animal { }

    enum AllAnimals { Cat, Dog, Pig };
    class Cat : Animal { }
    class Dog : Animal { }
    class Pig : Animal { }
}

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