我想用pyshark捕获数据包.但我无法在Windows 7上捕获数据包.

这是我的python代码

import pyshark
def NetCap():
    print 'capturing...'
    livecapture = pyshark.LiveCapture(interface="eth0", output_file='./test.pcapng')
    livecapture.sniff(packet_count=10)
    print 'end of capture.'
    print livecapture

if __name__ == "__main__":
    NetCap()

这是结果

capturing...
end of capture.
<LiveCapture (0 packets)>

Livecapture是0包.我不知道是怎么回事.请帮我.