C# Signature:
[DllImport("netapi32.dll", CharSet = CharSet.Unicode, SetLastError=true)]
static extern int NetWkstaUserEnum(
string servername,
int level,
out IntPtr bufptr,
int prefmaxlen,
out int entriesread,
out int totalentries,
ref int resume_handle);
VB Signature:
<DllImport("netapi32.dll", CharSet := CharSet.Unicode, SetLastError:=True)> _
Shared Function NetWkstaUserEnum(ByVal servername As String, ByVal level As Integer, <System.Runtime.InteropServices.Out()> ByRef bufptr As IntPtr, ByVal prefmaxlen As Integer, <System.Runtime.InteropServices.Out()> ByRef entriesread As Integer, <System.Runtime.InteropServices.Out()> ByRef totalentries As Integer, ByRef resume_handle As Integer) As Integer
End Function
User-Defined Types:
See sample code for types and constants.
Alternative Managed API:
WMI can do this sort of thing (the System.Management namespace in .Net 2.0)
Notes:
If you want to find the user logged in to the workstation, consider instead a WMI query ("select UserName from Win32_ComputerSystem"), which has certain advantages (runs faster, less ambigious results, doesn't require Interop if using .Net 2.0 System.Management namespace, etc.)
Tips & Tricks:
Please add some!
* On Windows 8+ when users log in with a MicrosoftAccount the username is returned like "MicrosoftAccount\user.email@thedomain.com" rather than the ID. This means for example that it won't match their directory name in C:\Users.
Sample Code:
class NetWorkstationUserEnum
{
[DllImport("netapi32.dll", CharSet = CharSet.Unicode, SetLastError=true)]
static extern int NetWkstaUserEnum(
string servername,
int level,
out IntPtr bufptr,
int prefmaxlen,
out int entriesread,
out int totalentries,
ref int resume_handle);
[DllImport("netapi32.dll")]
static extern int NetApiBufferFree(
IntPtr Buffer);
const int NERR_SUCCESS = 0;
const int ERROR_MORE_DATA = 234;
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct WKSTA_USER_INFO_0
{
public string wkui0_username;
}
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct WKSTA_USER_INFO_1
{
public string wkui1_username;
public string wkui1_logon_domain;
public string wkui1_oth_domains;
public string wkui1_logon_server;
}
void ScanHost(string hostName)
{
IntPtr bufptr = IntPtr.Zero;
int dwEntriesread;
int dwTotalentries = 0;
int dwResumehandle = 0;
int nStatus;
Type tWui1 = typeof(WKSTA_USER_INFO_1);
int nStructSize = Marshal.SizeOf(tWui1);
WKSTA_USER_INFO_1 wui1;
//this.listView1.Items.Clear();
do
{
nStatus = NetWkstaUserEnum(
hostName,
1,
out bufptr,
32768,
out dwEntriesread,
out dwTotalentries,
ref dwResumehandle);
//
// If the call succeeds,
//
if ((nStatus == NERR_SUCCESS) | (nStatus == ERROR_MORE_DATA))
{
if (dwEntriesread > 0)
{
IntPtr pstruct = bufptr;
//
// Loop through the entries.
//
for (int i = 0; i < dwEntriesread; i++)
{
wui1 = (WKSTA_USER_INFO_1)Marshal.PtrToStructure(pstruct, tWui1);
Console.WriteLine(wui1.wkui1_logon_domain + "\\" + wui1.wkui1_username);
pstruct = (IntPtr)((int)pstruct + nStructSize);
}
}
else
{
Console.WriteLine("A system error has occurred : " + nStatus);
}
}
if (bufptr != IntPtr.Zero)
NetApiBufferFree(bufptr);
} while (nStatus == ERROR_MORE_DATA);
}
static public void Main(string[] args)
{
string host = Environment.MachineName;
if (args.Length > 0)
{
host = args[0];
}
NetWorkstationUserEnum nws = new NetWorkstationUserEnum();
nws.ScanHost(host);
}
}
