With "GetVolumeInformation", the signature looks as follows:
[DllImport("kernel32.dll")]
private static extern long GetVolumeInformation(string PathName, StringBuilder VolumeNameBuffer, UInt32 VolumeNameSize, ref UInt32 VolumeSerialNumber, ref UInt32 MaximumComponentLength, ref UInt32 FileSystemFlags, StringBuilder FileSystemNameBuffer, UInt32 FileSystemNameSize);
Note that some of the parameters that you would think would be of type "int" must be passed as "UInt32", which corresponds to the .NET type "uint", and oftentimes a string must be passed as StringBuilder.
The actual method , with a string return value for convenience, looks like this:
public string GetVolumeSerial(string strDriveLetter)
{
uint serNum = 0;
uint maxCompLen = 0;
StringBuilder VolLabel = new StringBuilder(256); // Label
UInt32 VolFlags = new UInt32();
StringBuilder FSName = new StringBuilder(256); // File System Name
strDriveLetter+=":\\"; // fix up the passed-in drive letter for the API call
long Ret = GetVolumeInformation(strDriveLetter, VolLabel, (UInt32)VolLabel.Capacity, ref serNum, ref maxCompLen, ref VolFlags, FSName, (UInt32)FSName.Capacity);
return Convert.ToString(serNum);
}
