从其文本名称实例化一个类 [英] Instantiate a class from its textual name

问题描述

不要问我为什么，但我需要做以下事情:

Don't ask me why but I need to do the following:

string ClassName = "SomeClassName";  
object o = MagicallyCreateInstance("SomeClassName");

我想知道有多少种方法可以做到这一点，以及在哪种情况下使用哪种方法.

I want to know how many ways there are to do this is and which approach to use in which scenario.

示例:

• Activator.CreateInstance
• Assembly.GetExecutingAssembly.CreateInstance("")
• 如有任何其他建议，我们将不胜感激

这个问题并不是一个开放式的讨论，因为我相信只有这么多方法可以实现.

This question is not meant to be an open ended discussion because I am sure there are only so many ways this can be achieved.

推荐答案

以下是该方法的外观:

private static object MagicallyCreateInstance(string className)
{
    var assembly = Assembly.GetExecutingAssembly();

    var type = assembly.GetTypes()
        .First(t => t.Name == className);

    return Activator.CreateInstance(type);
}

上面的代码假设:

• 您正在寻找当前正在执行的程序集中的类(这可以调整 - 只需将 assembly 更改为您需要的任何内容)
• 在该程序集中只有一个类与您要查找的名称相同
• 该类有一个默认构造函数

• you are looking for a class that is in the currently executing assembly (this can be adjusted - just change assembly to whatever you need)
• there is exactly one class with the name you are looking for in that assembly
• the class has a default constructor

更新:

以下是获取从给定类派生的所有类(并在同一程序集中定义)的方法:

Here's how to get all the classes that derive from a given class (and are defined in the same assembly):

private static IEnumerable<Type> GetDerivedTypesFor(Type baseType)
{
    var assembly = Assembly.GetExecutingAssembly();

    return assembly.GetTypes()
        .Where(baseType.IsAssignableFrom)
        .Where(t => baseType != t);
}

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