/// <summary>
        ///    返回本机的mac物理路径
        /// </summary>
        /// <returns></returns>
        private string GetMac()
        {
            string mac = null;
            //[DllImport("System.Management.dll")]  
            ManagementObjectSearcher query = new ManagementObjectSearcher("SELECT * FROM Win32_NetworkAdapterConfiguration");
            ManagementObjectCollection queryCollection = query.Get();
            foreach (ManagementObject mo in queryCollection)
            {
                if (mo["IPEnabled"].ToString() == "True")
                    mac = mo["MacAddress"].ToString();
            }
            return (mac);  
        }