Работа с ComboBox

string diskName = string.Empty;
    kvp = new List<string>();
    comboBox1.Items.Clear();
    foreach (System.Management.ManagementObject drive in
              new System.Management.ManagementObjectSearcher(
               "select * from Win32_DiskDrive where InterfaceType='USB'").Get())
    {
        foreach (System.Management.ManagementObject partition in
           new System.Management.ManagementObjectSearcher(
            "ASSOCIATORS OF {Win32_DiskDrive.DeviceID='" + drive["DeviceID"]
              + "'} WHERE AssocClass = Win32_DiskDriveToDiskPartition").Get())
        {
            foreach (System.Management.ManagementObject disk in
               new System.Management.ManagementObjectSearcher(
                "ASSOCIATORS OF {Win32_DiskPartition.DeviceID='"
                  + partition["DeviceID"]
                  + "'} WHERE AssocClass = Win32_LogicalDiskToPartition").Get())
            {
                //Получение буквы устройства
                diskName = disk["Name"].ToString().Trim();
                comboBox1.Items.Add(diskName + " (" + drive["Model"] + ")");
                kvp.Add(diskName);
            }
        }
    }

ManagementObjectSearcher theSearcher = new ManagementObjectSearcher("SELECT * FROM Win32_DiskDrive WHERE InterfaceType='USB'");
                foreach (ManagementObject currentObject in theSearcher.Get())
                {
                    ManagementObject theSerialNumberObjectQuery = new ManagementObject("Win32_PhysicalMedia.Tag='" + currentObject["DeviceID"] + "'");
                    MessageBox.Show(theSerialNumberObjectQuery["SerialNumber"].ToString());
                }