CreateInstance requires an Instance binding flag

kathleen@mvps.org — Wed, 02 Aug 2006 06:00:00 GMT

I was beating my head against Activator.CreateInstance this morning. It was just telling me the constructor didn’t exist, when I knew it existed. The constructor in this case is private to prohibit any use outside the class. I’m using CreateInstance when I’m creating the class from its generic base class. It also has parameters, so the simplest overload I can use is

Public Shared Function CreateInstance ( _

type As Type, _

bindingAttr As BindingFlags, _

binder As Binder, _

args As Object(), _

culture As CultureInfo _

) AsObject

This isn’t quite as ugly to use as it seems because you can pass Nothing (null in C#) for both the binder and the culture. I tried:

Return DirectCast( _

Activator.CreateInstance(GetType(TList), _

Reflection.BindingFlags.NonPublic, _

Nothing, _

New Object() {dr}, _

Nothing), TList)

The problem I encountered is that you also need to specify BindingFlags.Instance.

Return DirectCast( _

Activator.CreateInstance(GetType(TList), _

Reflection.BindingFlags.NonPublic Or Reflection.BindingFlags.Instance, _

Nothing, _

New Object() {dr}, _

Nothing), TList)

In retrospect, this isn’t really onerous, it’s just something you need to know when using this method.

Bemused Musings

CreateInstance requires an Instance binding flag