I create a hostednetwork in windows 8-1.
after that i select the new virtual wifi and ethernet but there is no option to making bridge.
I have this problem because of the windows 8.1 did not support ad hoc network:(
I create a hostednetwork with the below command
netsh wlan set hostednetwork mode=allow ssid=sam key=qwert12345 keyusage=persistent
netsh wlan start hostednetwork