Question

I have something along the lines of this:

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

and

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

    # region Constructors

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

    internal xxx()
    {
    }

    ...
}

And I get:

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

Any ideas?

Answer 1

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

Exceptions

MissingMethodException: No matching
public constructor was found.

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

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);

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)