CNiKnob::ControlMetrics

   CNiControlMetrics metrics = knob.ControlMetrics;
   CNiString output;
   output << "Minimum: " << metrics.Minimum << ", Maximum: " << metrics.Maximum;
   AfxMessageBox(output);
   metrics.Reset();

If you do not initialize a CNiControlMetrics object from an existing object, a CNiObjectNotInUsableState exception will be thrown when you attempt to use the instance of the CNiControlMetrics. For example:

   CNiControlMetrics metrics;

   // This will throw a CNiObjectNotInUsableState exception because
   // the CNiControlMetrics object was not initialize from an
   // existing object.
   metrics.Reset();