C# Signature:

    [DllImport("Netapi32.dll")]
       extern static int NetUserEnum([MarshalAs(UnmanagedType.LPWStr)]
       string servername,
       int level,
       int filter,
       out IntPtr bufptr,
       int prefmaxlen,
       out int entriesread,
       out int totalentries,
       out int resume_handle);

VB Signature:

    Public Declare Function NetUserEnum Lib "Netapi32.dll" ( _
    <MarshalAs(UnmanagedType.LPWStr)> ByVal servername As String, _
    ByVal level As Integer, _
    ByVal filter As Integer, _
    ByRef bufptr As IntPtr, _
    ByVal prefmaxlen As Integer, _
    ByRef entriesread As Integer, _
    ByRef totalentries As Integer, _
    ByRef resume_handle As Integer) As Integer

User-Defined Types:

// Passing -1 as prefmaxlen makes the system allocate the buffer.

        // LMCONS.h

const int MAX_PREFERRED_LENGTH = -1;

// You'll need these for the return values

        // LMERR.h

const int NERR_Success = 0; /* Success */

const int NERR_BASE = 2100;

const int NERR_InvalidComputer = (NERR_BASE+251); /* This computer name is invalid. */

        // WINERROR.h

const int ERROR_ACCESS_DENIED = 5;

const int ERROR_MORE_DATA = 234;

Notes:

None.

Tips & Tricks:

Please add some!

Sample Code:

    ArrayList users = new ArrayList();
    int EntriesRead;
    int TotalEntries;
    int Resume;
    IntPtr bufPtr;

    NetUserEnum(server, 0, 2, out bufPtr, -1, out EntriesRead, out TotalEntries, out Resume);
    if(EntriesRead> 0)
    {
        USER_INFO_0[] Users = new USER_INFO_0[EntriesRead];
        IntPtr iter = bufPtr;
        for(int i=0; i < EntriesRead; i++)
        {
            Users[i] = (USER_INFO_0)Marshal.PtrToStructure(iter, typeof(USER_INFO_0));
            iter = (IntPtr)((int)iter + Marshal.SizeOf(typeof(USER_INFO_0)));

            users.Add(Users[i].Username);
        }
        NetApiBufferFree(bufPtr);
    }

Alternative Managed API:

Do you know one? Please contribute it!