Activator.CreateInstance（字符串）和Activator.CreateInstance< T>（）的区别 [英] Activator.CreateInstance(string) and Activator.CreateInstance<T>() difference

问题描述

没有，这不是一个关于仿制药的问题。

No, this is not a question about generics.

我有几类内部构造工厂模式（我不希望他们被实例化如果不是通过工厂）。

I have a Factory pattern with several classes with internal constructors (I don't want them being instantiated if not through the factory).

我的问题是，的CreateInstance 失败，出现此对象定义无参数的构造函数错误，除非我通过对非公有制参数真。

My problem is that CreateInstance fails with a "No parameterless constructor defined for this object" error unless I pass "true" on the non-public parameter.

示例

// Fails
Activator.CreateInstance(type);

// Works
Activator.CreateInstance(type, true);

我想使工厂通用，使之成为简单一点，就像这样：

I wanted to make the factory generic to make it a little simpler, like this:

public class GenericFactory<T> where T : MyAbstractType
{
    public static T GetInstance()
    {
        return Activator.CreateInstance<T>();
    }
}

不过，我无法找到如何传递真参数为它接受非公共构造函数（内部）。

However, I was unable to find how to pass that "true" parameter for it to accept non-public constructors (internal).

我错过了什么，或者是不可能的？

Did I miss something or it isn't possible?

推荐答案

要解决这个问题，想不出你只是改变你的用法，例如：

To get around this, couldnt you just alter your usage as such:

public class GenericFactory<T> where T : MyAbstractType
{
    public static T GetInstance()
    {
        return Activator.CreateInstance(typeof(T), true);
    }
}

您的工厂方法仍然是通用的，但电话对激活不会使用一般超载。但你仍然要达到相同的结果。

Your factory method will still be generic, but the call to the activator will not use the generic overload. But you should still achieve the same results.

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