The best way to resolve display username by SID?

Question

I read a list of SIDs from the registry, HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList.

How would one resolve the display username (e.g. DOMAIN\user, BUILT-IN\user) given the SID string in C#?

Answer 1

The Win32 API function LookupAccountSid() is used to find the name that corresponds to a SID.

LookupAccountSid() has the following signature:

BOOL LookupAccountSid(LPCTSTR lpSystemName, PSID Sid,LPTSTR Name, LPDWORD cbName,
                       LPTSTR ReferencedDomainName, LPDWORD cbReferencedDomainName,
                       PSID_NAME_USE peUse);

MSDN Ref.

Here's the P/Invoke reference (with sample code): http://www.pinvoke.net/default.aspx/advapi32.LookupAccountSid

[DllImport("advapi32.dll", CharSet=CharSet.Auto, SetLastError = true)]
static extern bool LookupAccountSid (
  string lpSystemName,
  [MarshalAs(UnmanagedType.LPArray)] byte[] Sid,
  StringBuilder lpName,
  ref uint cchName,
  StringBuilder ReferencedDomainName,
  ref uint cchReferencedDomainName,
  out SID_NAME_USE peUse); 

Answer 2

Just found it on the pinvoke.net.

Alternative Managed API: Available in .Net 2.0:

using System.Security.Principal;

// convert the user sid to a domain\name
string account = new SecurityIdentifier(stringSid).Translate(typeof(NTAccount)).ToString();