c# - "The input array was empty" ArgumentException when making a invoked cross thread call

Question

I have two separate threads and sometimes I need to call members from the other thread. I do this via the normal method of invoking. Here's the basic setup:

void Foo() //On thread 1
{
     if (this.InvokeRequired)
          this.Invoke(new Action(Foo2));
     else
          Foo2();
}

void Foo2(){/*Do Work*/} //Accesses members on thread 2

I'm getting the error "ArgumentException was unhandled: The input array was empty". The thing is, the method I'm trying to invoke has no parameters, and as per documentation, this shouldn't be an issue.

I even tried replacing:

this.Invoke(new Action(Foo2));

with

this.Invoke(new Action(Foo2), null);

(the documentation says if there are no parameters, then pass null, and I'm still getting the same error)

Here's the top of the StackTrace:

at System.Windows.Forms.Control.MarshaledInvoke(Control caller, Delegate method, Object[] args, Boolean synchronous) at System.Windows.Forms.Control.Invoke(Delegate method, Object[] args)

So, it says the array (for parameters I presume) is empty, but this is in fact correct because I'm calling a method with no parameters... What's the catch here?