使用反射在内部类中使用参数实例化构造函数 [英] Instantiating a constructor with parameters in an internal class with reflection

问题描述

我有一些类似的东西:

object[] parameter = new object[1];
parameter[0] = x;
object instantiatedType =
Activator.CreateInstance(typeToInstantiate, parameter);

和

internal class xxx : ICompare<Type>
{
    private object[] x;

    # region Constructors

    internal xxx(object[] x)
    {
        this.x = x;
    }

    internal xxx()
    {
    }

    ...
}

我得到:

抛出异常:System.MissingMethodException:未找到类型xxxx.xxx"的构造函数..

threw exception: System.MissingMethodException: Constructor on type 'xxxx.xxx' not found..

有什么想法吗?

推荐答案

问题在于 Activator.CreateInstance(Type, object[]) 不考虑非公共构造函数.

The issue is that Activator.CreateInstance(Type, object[]) does not consider non-public constructors.

例外

MissingMethodException: 不匹配找到公共构造函数.

MissingMethodException: No matching public constructor was found.

这很容易通过将构造函数更改为publicvisibility 来显示；然后代码可以正常工作.

This is easily shown by changing the constructor to publicvisibility; the code then works correctly.

这是一种解决方法(已测试):

Here's one workaround (tested):

 BindingFlags flags = BindingFlags.NonPublic | BindingFlags.Instance;
 CultureInfo culture = null; // use InvariantCulture or other if you prefer
 object instantiatedType =   
   Activator.CreateInstance(typeToInstantiate, flags, null, parameter, culture);

如果您只需要无参数构造函数，这也可以:

If you only require the parameterless constructor this will work as well:

//using the overload: public static object CreateInstance(Type type, bool nonPublic)
object instantiatedType = Activator.CreateInstance(typeToInstantiate, true)

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