G2 Gensym post from C#

Question

I am trying to past a message to system G2, but I get error, No overload for method 'PostMessage' takes 2 arguments. Can you please help, thks

  private void PostMsgBtn_Click(object sender, EventArgs e)
    {
        object[] C1_ob = new object[1];
        C1_ob[0] = 1;

        axG2Gateway1.PostMessage(MsgToPost.Text , ref (C1_ob));
        
    }