>    protected override void OnTextChanged(EventArgs e)
>    {
>        if (this.Parent is IMyInterface)
>        {
>            ((IMyInterface)this.Parent).MyMethod(true);
>        }
>        base.OnTextChanged(e);
>    }

>    protected override void OnTextChanged(EventArgs e)
>    {
          IMyInterface o;
>        if ( ( o = this.Parent as IMyInterface) != null )
>        {
>           o.MyMethod(true);
>        }
>        base.OnTextChanged(e);
>    }