How to register the events given by dll

Question

I'm developing one application in which i'm developing my GUI portion in VB.Net while i have written dll in VC++ to take care of my all the real time interface related requirements. Now I have coded in my dll that whenever data is received on the port it will create one event. Now i don't know how to make sense to my GUI application in VB.Net about this event raised from the DLL in VC++. I'm new to .Net programming so i would appreciate the help in detail and prefer with the code example. Thanks in advance for your help, regards, Krunal