IntPtr GetSIDInformation(string account)
{
//pointer an size for the SID
IntPtr sid = IntPtr.Zero;
int sidSize = 0;
//StringBuilder and size for the domain name
StringBuilder domainName = new StringBuilder();
int nameSize = 0;
//account-type variable for lookup
int accountType = 0;
//get required buffer size
LookupAccountName(String.Empty, account, sid, ref sidSize, domainName, ref nameSize, ref accountType);
//allocate buffers
domainName = new StringBuilder(nameSize);
sid = Marshal.AllocHGlobal(sidSize);
//lookup the SID for the account
bool result = LookupAccountName(String.Empty, account, sid, ref sidSize, domainName, ref nameSize, ref accountType);
if(!result)
{
Marshal.ThrowExceptionForHR(GetLastError());
}
return sid;
}