C#获取硬盘序列号

using System;
using System.Runtime.InteropServices;

namespace ArLi.CommonPrj {

#region how use this?
/*
string sVol = getvol.GetVolOf(\"C\");
*/
#endregion

public class getvol{

[DllImport(\"kernel32.dll\")]
private static extern int GetVolumeInformation(
  string lpRootPathName,
  string lpVolumeNameBuffer,
  int nVolumeNameSize,
  ref int lpVolumeSerialNumber,
  int lpMaximumComponentLength,
  int lpFileSystemFlags,
  string lpFileSystemNameBuffer,
  int nFileSystemNameSize
  );

public static string GetVolOf(string drvID){
  const int MAX_FILENAME_LEN = 256;
  int retVal = 0;
  int a =0;
  int b =0;
  string str1 = null;
  string str2 = null;


  int i = GetVolumeInformation(
  drvID + @\":\\\",
  str1,
  MAX_FILENAME_LEN,
  ref retVal,
  a,
  b,
  str2,
  MAX_FILENAME_LEN
  );

  return retVal.ToString(\"x\");
}
}
}