SNMP discovery is not part of SNMP standard. The common practice is to send broadcast GET message (even Microsoft uses the same way in SCOM, http://www.systemcentercentral.com/snmp-series-part-2-behind-the-scenes-of-snmp-discovery-proxy-and-device-availability-monitoring-in-opsmgr-2007/).
You can perform the same discovery by using
https://github.com/lextm/sharpsnmplib/blob/master/SharpSnmpLib/Messaging/Discoverer.cs
You can perform the same discovery by using
Discoverer class.https://github.com/lextm/sharpsnmplib/blob/master/SharpSnmpLib/Messaging/Discoverer.cs