使用WMI对象为什么提取不到计算机的MAC地址

Private Sub cmdGetMAC_Click()
Dim strmac As String
Dim objwmiservice As Object
Dim colitems As Object
Dim objitem As Object

Set objwmiservice = GetObject("winmgmts:{impersonationlevel=impersonate}!\\.\root\cimv2")
Set colitems = objwmiservice.ExecQuery("Select * From Win32_NetworkAdapterConfiguration Where IPEnabled = True")

For Each objitem In colitems
     strmac = objitem.macaddress
     lstMAC.AddItem Replace(Trim(strmac), ":", "-")
Next
End Sub