asp.net how to read the serial number of the specified hard disk drive

using System; 
using System.IO; 
using System.Runtime.InteropServices; 
using System.Text; 
using Microsoft.Win32;

namespace Wjb.ReadOrWriteIniAndReg 
( 
/**//// 
/ / / Read the serial number of the specified hard disk drive 
/ / / 
public class HardDiskVal 
( 

[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 
); 
/**//// 
/ / / Get the hard drive serial number for the drvID, default is C 
/ / / 
/ / / 
/ / / 
public string HDVal (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 (); 
) 
public string HDVal () 
( 
const int MAX_FILENAME_LEN = 256; 
int retVal = 0; 
int a = 0; 
int b = 0; 
string str1 = null; 
string str2 = null;

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

return retVal.ToString (); 
) 
)