How can I invoke a private method with no params?

private void MonitorDBOffline()

        {

        ... Do Stuff

}

Test Method(){

...setup

 Isolate.Invoke.Method(c, "MonitorDBOffline", null);

}

This test method results in the error:

No overloads of method "MonitorDBOffline" receive argument types {Object}

Possible candidates are:

- MonitorDBOffline()

How can I use the Invoke method with no parameteres.

Thanks,