What's wrong in my code? If you can help?

See my code below:
// fc - a feature class w/ multiple feature records
ESRI.ArcGIS.Location.RouteEventSourceClass rteEventSourceClass;
rteEventSourceClass = fc as ESRI.ArcGIS.Location.RouteEventSourceClass;
But the value of the rteEventSourceClass is null. Did I do something wrong? I want to retrieve the rteEventSourceClass values. Thanks.