private void ReadHdId()
    {
        String HDid;
        System.Management.ManagementClass cimobject = new System.Management.ManagementClass("Win32_PhysicalMedia");
        System.Management.ManagementObjectCollection moc = cimobject.GetInstances();
        foreach (System.Management.ManagementObject mo in moc)
        {
            HDid = (string)mo.Properties["SerialNumber"].Value;
            Response.Write("硬盘ID:" + HDid + "<br>");
        }
    }