Connecting to wifi network - Measure connection time

I'm connecting to WiFi network. How can I measure the connection time? I mean, I need to get the time the connection takes.

I tried to use the following events (Of WMI):

MSNdis_StatusDot11AssociationStart
MSNdis_StatusDot11AssociationCompletion

But the second event  didn't work. I mean, I get the info when the connection started but didn't get any info when the connection completed.

I used to the following classes and I faced the same issue:

MSNdis_StatusDot11ConnectionStart
MSNdis_StatusDot11ConnectionCompletion 

Can you please help?

Regards,
Nadeem Bader